Docs: Document that `has_block()` does not check reusable blocks.

Since the function only checks the raw, non-parsed post content, reusable blocks are just a `core/block` type and nothing more at that point.

In order to also check reusable blocks, the content needs to be parsed using `parse_blocks()` first.

Props vyskoczilova, peterwilsoncc.
Fixes #53140.
Built from https://develop.svn.wordpress.org/trunk@51046


git-svn-id: http://core.svn.wordpress.org/trunk@50655 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/blocks.php

@@ -374,7 +374,8 @@ function unregister_block_type( $name ) {
  *
  * @see parse_blocks()
  *
- * @param int|string|WP_Post|null $post Optional. Post content, post ID, or post object. Defaults to global $post.
+ * @param int|string|WP_Post|null $post Optional. Post content, post ID, or post object.
+ *                                      Defaults to global $post.
  * @return bool Whether the post has blocks.
  */
 function has_blocks( $post = null ) {
@@ -392,15 +393,16 @@ function has_blocks( $post = null ) {
  * Determine whether a $post or a string contains a specific block type.
  *
  * This test optimizes for performance rather than strict accuracy, detecting
- * the block type exists but not validating its structure. For strict accuracy,
- * you should use the block parser on post content.
+ * whether the block type exists but not validating its structure and not checking
+ * reusable blocks. For strict accuracy, you should use the block parser on post content.
  *
  * @since 5.0.0
  *
  * @see parse_blocks()
  *
- * @param string                  $block_name Full Block type to look for.
- * @param int|string|WP_Post|null $post Optional. Post content, post ID, or post object. Defaults to global $post.
+ * @param string                  $block_name Full block type to look for.
+ * @param int|string|WP_Post|null $post       Optional. Post content, post ID, or post object.
+ *                                            Defaults to global $post.
  * @return bool Whether the post content contains the specified block.
  */
 function has_block( $block_name, $post = null ) {

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-alpha-51045';
+$wp_version = '5.8-alpha-51046';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.