Expand block template examples (#13494)

* Expand block template examples

Adds examples for PHP and JS for using templates.

Fixes #8251

* Consolidate examples and cleanup

Update function names to be consistent across example.

docs/designers-developers/developers/block-api/block-templates.md

@@ -17,18 +17,50 @@ Planned additions:
 
 Templates can be declared in JS or in PHP as an array of blockTypes (block name and optional attributes).
 
+The first example in PHP creates a template for posts that includes an image block to start, you can add as many or as few blocks to your template as needed.
+
+PHP example:
+
+```php
+<?php
+function myplugin_register_template() {
+    $post_type_object = get_post_type_object( 'post' );
+    $post_type_object->template = array(
+        array( 'core/image' ),
+    );
+}
+add_action( 'init', 'myplugin_register_template' );
+```
+
+The following example in JavaScript creates a new block using [InnerBlocks](/packages/editor/src/components/inner-blocks) and templates, when inserted creates a set of blocks based off the template.
+
 ```js
-const template = [
-  [ 'block/name', {} ], // [ blockName, attributes ]
+const el = wp.element.createElement;
+const { registerBlockType } = wp.blocks;
+const { InnerBlocks } = wp.editor;
+
+const BLOCKS_TEMPLATE = [
+	[ 'core/image', {} ],
+	[ 'core/paragraph', { placeholder: 'Image Details' } ],
 ];
-```
 
-```php
-'template' => array(
-	array( 'block/name' ),
-),
+registerBlockType( 'myplugin/template', {
+	title: 'My Template Block',
+	category: 'widgets',
+	edit: ( props ) => {
+		return el( InnerBlocks, {
+			template: BLOCKS_TEMPLATE,
+			templateLock: false
+		});
+	},
+	save: ( props ) => {
+		return el( InnerBlocks.Content, {} );
+	},
+});
 ```
 
+See the [Meta Block Tutorial](/docs/designers-developers/developers/tutorials/metabox/meta-block-5-finishing.md) for a full example of a template in use.
+
 ## Custom Post types
 
 A custom post type can register its own template during registration:
@@ -61,20 +93,7 @@ add_action( 'init', 'myplugin_register_book_post_type' );
 Sometimes the intention might be to lock the template on the UI so that the blocks presented cannot be manipulated. This is achieved with a `template_lock` property.
 
 ```php
-'template_lock' => 'all', // or 'insert' to allow moving
-```
-
-*Options:*
-
-- `all` — prevents all operations. It is not possible to insert new blocks, move existing blocks, or delete blocks.
-- `insert` — prevents inserting or removing blocks, but allows moving existing blocks.
-
-## Existing Post Types
-
-It is also possible to assign a template to an existing post type like "posts" and "pages":
-
-```php
-function my_add_template_to_posts() {
+function myplugin_register_template() {
 	$post_type_object = get_post_type_object( 'post' );
 	$post_type_object->template = array(
 		array( 'core/paragraph', array(
@@ -83,9 +102,14 @@ function my_add_template_to_posts() {
 	);
 	$post_type_object->template_lock = 'all';
 }
-add_action( 'init', 'my_add_template_to_posts' );
+add_action( 'init', 'myplugin_register_template' );
 ```
 
+*Options:*
+
+- `all` — prevents all operations. It is not possible to insert new blocks, move existing blocks, or delete blocks.
+- `insert` — prevents inserting or removing blocks, but allows moving existing blocks.
+
 ## Nested Templates
 
 Container blocks like the columns blocks also support templates. This is achieved by assigning a nested template to the block.