Posts, Post Types: Mark the `wp_global_styles` post type as `_builtin`.

All native or “built-in” post types should be marked as such.

Follow up to [52041].

See #54336.
Built from https://develop.svn.wordpress.org/trunk@52108


git-svn-id: http://core.svn.wordpress.org/trunk@51700 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/post.php

@@ -452,6 +452,7 @@ function create_initial_post_types() {
 			'label'        => __( 'Global Styles' ),
 			'description'  => 'CPT to store user design tokens',
 			'public'       => false,
+			'_builtin'     => true, /* internal use only. don't use this when registering your own post type. */
 			'show_ui'      => false,
 			'show_in_rest' => false,
 			'rewrite'      => false,

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-52107';
+$wp_version = '5.9-alpha-52108';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.