Templates: Deprecate _inject_theme_attribute_in_block_template_content.

It can be replaced by passing `_inject_theme_attribute_in_template_part_block` as second argument to `traverse_and_serialize_blocks()`.

Per WordPress 6.4 Beta 1, there aren't going to be any more calls in Core to `_inject_theme_attribute_in_block_template_content()`.

Note that `_inject_theme_attribute_in_block_template_content` has always had `@access private` set in its PHPDoc.

Props gziolo.
Fixes #59452.
Built from https://develop.svn.wordpress.org/trunk@56719


git-svn-id: http://core.svn.wordpress.org/trunk@56231 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/block-template-utils.php

@@ -475,12 +475,19 @@ function _flatten_blocks( &$blocks ) {
  * stylesheet as a theme attribute into each wp_template_part
  *
  * @since 5.9.0
+ * @deprecated 6.4.0 Use traverse_and_serialize_blocks( parse_blocks( $template_content ), '_inject_theme_attribute_in_template_part_block' ) instead.
  * @access private
  *
  * @param string $template_content serialized wp_template content.
  * @return string Updated 'wp_template' content.
  */
 function _inject_theme_attribute_in_block_template_content( $template_content ) {
+	_deprecated_function(
+		__FUNCTION__,
+		'6.4.0',
+		'traverse_and_serialize_blocks( parse_blocks( $template_content ), "_inject_theme_attribute_in_template_part_block" )'
+	);
+
 	$has_updated_content = false;
 	$new_content         = '';
 	$template_blocks     = parse_blocks( $template_content );

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.4-alpha-56718';
+$wp_version = '6.4-alpha-56719';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.