docs(lambda): fromAsset exclude (aws#26473)

We discussed for the need to document `exclude` patterns using a negation in [the PR](aws#26365 (comment)).

I also could not find documentation for the `exclude` property itself, so I added them.

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/aws-cdk-lib/aws-lambda/README.md

@@ -1134,3 +1134,32 @@ new lambda.Function(this, 'Lambda', {
   code: lambda.Code.fromAsset(path.join(__dirname, 'lambda-handler')),
 });
 ```
+
+## Exclude Patterns for Assets
+
+When using `lambda.Code.fromAsset(path)` an `exclude` property allows you to ignore particular files for assets by providing patterns for file paths to exclude. Note that this has no effect on `Assets` bundled using the `bundling` property.
+
+The `ignoreMode` property can be used with the `exclude` property to specify the file paths to ignore based on the [.gitignore specification](https://git-scm.com/docs/gitignore) or the [.dockerignore specification](https://docs.docker.com/engine/reference/builder/#dockerignore-file). The default behavior is to ignore file paths based on simple glob patterns.
+
+```ts
+new lambda.Function(this, 'Function', {
+  code: lambda.Code.fromAsset(path.join(__dirname, 'my-python-handler'), {
+    exclude: ['*.ignore'],
+    ignoreMode: IgnoreMode.DOCKER, // Default is IgnoreMode.GLOB
+  }),
+  runtime: lambda.Runtime.PYTHON_3_9,
+  handler: 'index.handler',
+});
+```
+
+You can also write to include only certain files by using a negation.
+
+```ts
+new lambda.Function(this, 'Function', {
+  code: lambda.Code.fromAsset(path.join(__dirname, 'my-python-handler'), {
+    exclude: ['*', '!index.py'],
+  }),
+  runtime: lambda.Runtime.PYTHON_3_9,
+  handler: 'index.handler',
+});
+```

packages/aws-cdk-lib/rosetta/aws_lambda/default.ts-fixture

@@ -1,7 +1,7 @@
 // Fixture with packages imported, but nothing else
 import * as path from 'path';
 import { Construct } from 'constructs';
-import { Aspects, CfnOutput, DockerImage, Duration, RemovalPolicy, Stack } from 'aws-cdk-lib';
+import { Aspects, CfnOutput, DockerImage, Duration, IgnoreMode, RemovalPolicy, Stack } from 'aws-cdk-lib';
 import * as lambda from 'aws-cdk-lib/aws-lambda';
 import * as iam from 'aws-cdk-lib/aws-iam';
 import { LAMBDA_RECOGNIZE_VERSION_PROPS, LAMBDA_RECOGNIZE_LAYER_VERSION } from 'aws-cdk-lib/cx-api';