doc: remove boilerplate from landing page snippet

generator/internal/scaffold_generator.cc

@@ -618,7 +618,7 @@ The following shows the code that you'll run in the
 `google/cloud/$library$/quickstart/` directory,
 which should give you a taste of the $title$ C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 
@@ -923,6 +923,7 @@ void GenerateQuickstartSkeleton(
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/$library$/ EDIT HERE .h"
 #include "google/cloud/project.h"
 #include <iostream>
@@ -948,6 +949,7 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]
 )""";
   google::protobuf::io::OstreamOutputStream output(&os);
   google::protobuf::io::Printer printer(&output, '$');

google/cloud/accessapproval/doc/main.dox

@@ -38,7 +38,7 @@ The following shows the code that you'll run in the
 `google/cloud/accessapproval/quickstart/` directory,
 which should give you a taste of the Access Approval API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/accessapproval/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/accessapproval/access_approval_client.h"
 #include "google/cloud/project.h"
 #include <iostream>
@@ -36,3 +37,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/accesscontextmanager/doc/main.dox

@@ -37,7 +37,7 @@ The following shows the code that you'll run in the
 `google/cloud/accesscontextmanager/quickstart/` directory,
 which should give you a taste of the Access Context Manager API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/accesscontextmanager/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/accesscontextmanager/access_context_manager_client.h"
 #include <iostream>
 
@@ -36,3 +37,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/apigateway/doc/main.dox

@@ -36,7 +36,7 @@ The following shows the code that you'll run in the
 `google/cloud/apigateway/quickstart/` directory,
 which should give you a taste of the API Gateway API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/apigateway/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/apigateway/api_gateway_client.h"
 #include <iostream>
 
@@ -37,3 +38,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/apigeeconnect/doc/main.dox

@@ -40,7 +40,7 @@ The following shows the code that you'll run in the
 `google/cloud/apigeeconnect/quickstart/` directory,
 which should give you a taste of the Apigee Connect API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/apigeeconnect/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/apigeeconnect/connection_client.h"
 #include <iostream>
 
@@ -37,3 +38,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/apikeys/doc/main.dox

@@ -36,7 +36,7 @@ The following shows the code that you'll run in the
 `google/cloud/apikeys/quickstart/` directory,
 which should give you a taste of the API Keys API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/apikeys/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/apikeys/api_keys_client.h"
 #include <iostream>
 
@@ -35,3 +36,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/appengine/doc/main.dox

@@ -36,7 +36,7 @@ The following shows the code that you'll run in the
 `google/cloud/appengine/quickstart/` directory,
 which should give you a taste of the App Engine Admin API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/appengine/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/appengine/services_client.h"
 #include <iostream>
 
@@ -36,3 +37,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/artifactregistry/doc/main.dox

@@ -37,7 +37,7 @@ The following shows the code that you'll run in the
 `google/cloud/artifactregistry/quickstart/` directory,
 which should give you a taste of the Artifact Registry API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/artifactregistry/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/artifactregistry/artifact_registry_client.h"
 #include <iostream>
 
@@ -37,3 +38,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/asset/doc/main.dox

@@ -37,7 +37,7 @@ The following shows the code that you'll run in the
 `google/cloud/asset/quickstart/` directory,
 which should give you a taste of the Cloud Asset API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/asset/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/asset/asset_client.h"
 #include "google/cloud/project.h"
 #include <iostream>
@@ -39,3 +40,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/assuredworkloads/doc/main.dox

@@ -39,7 +39,7 @@ The following shows the code that you'll run in the
 `google/cloud/assuredworkloads/quickstart/` directory,
 which should give you a taste of the Assured Workloads API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/assuredworkloads/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/assuredworkloads/assured_workloads_client.h"
 #include <iostream>
 
@@ -37,3 +38,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/automl/doc/main.dox

@@ -37,7 +37,7 @@ The following shows the code that you'll run in the
 `google/cloud/automl/quickstart/` directory,
 which should give you a taste of the Cloud AutoML API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/automl/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/automl/auto_ml_client.h"
 #include <iostream>
 
@@ -36,3 +37,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/baremetalsolution/doc/main.dox

@@ -37,7 +37,7 @@ The following shows the code that you'll run in the
 `google/cloud/baremetalsolution/quickstart/` directory,
 which should give you a taste of the Bare Metal Solution API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/baremetalsolution/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/baremetalsolution/bare_metal_solution_client.h"
 #include <iostream>
 
@@ -37,3 +38,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/batch/doc/main.dox

@@ -35,7 +35,7 @@ The following shows the code that you'll run in the
 `google/cloud/batch/quickstart/` directory,
 which should give you a taste of the Batch API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/batch/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/batch/batch_client.h"
 #include <iostream>
 
@@ -36,3 +37,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/beyondcorp/doc/main.dox

@@ -39,7 +39,7 @@ The following shows the code that you'll run in the
 `google/cloud/beyondcorp/quickstart/` directory,
 which should give you a taste of the BeyondCorp API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/beyondcorp/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/beyondcorp/app_connectors_client.h"
 #include <iostream>
 
@@ -37,3 +38,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/bigquery/doc/main.dox

@@ -47,7 +47,7 @@ The following shows the code that you'll run in the
 `google/cloud/bigquery/quickstart/` directory, which should give you a taste of
 the Cloud BigQuery C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 @endparblock
 
 ## Environment Variables

google/cloud/bigquery/quickstart/quickstart.cc

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! [START bigquerystorage_quickstart]
+//! [START bigquerystorage_quickstart] [all]
 #include "google/cloud/bigquery/bigquery_read_client.h"
 #include <iostream>
 
@@ -70,4 +70,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
-//! [END bigquerystorage_quickstart]
+//! [END bigquerystorage_quickstart] [all]

google/cloud/bigtable/doc/bigtable-main.dox

@@ -53,7 +53,7 @@ The following shows the code that you'll run in the
 `google/cloud/bigtable/quickstart/` directory,
 which should give you a taste of the Cloud Bigtable C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## API Notes
 

google/cloud/bigtable/quickstart/quickstart.cc

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// [START bigtable_quickstart]
+//! [START bigtable_quickstart] [all]
 #include "google/cloud/bigtable/table.h"
 
 int main(int argc, char* argv[]) try {
@@ -57,4 +57,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
-// [END bigtable_quickstart]
+//! [END bigtable_quickstart] [all]

google/cloud/billing/doc/main.dox

@@ -38,7 +38,7 @@ The following shows the code that you'll run in the
 `google/cloud/billing/quickstart/` directory,
 which should give you a taste of the Cloud Billing Budget API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables
 

google/cloud/billing/quickstart/quickstart.cc

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! [all]
 #include "google/cloud/billing/cloud_billing_client.h"
 #include <iostream>
 
@@ -35,3 +36,4 @@ int main(int argc, char* argv[]) try {
   std::cerr << "google::cloud::Status thrown: " << status << "\n";
   return 1;
 }
+//! [all]

google/cloud/binaryauthorization/doc/main.dox

@@ -37,7 +37,7 @@ The following shows the code that you'll run in the
 `google/cloud/binaryauthorization/quickstart/` directory,
 which should give you a taste of the Binary Authorization API C++ client library API.
 
-@include quickstart.cc
+@snippet quickstart.cc all
 
 ## Environment Variables