Docs: Correct documentation for `wp_get_post_parent_id()`.

The `$post` parameter is required and does not have a default value.

Follow-up to [42397].

Props denisco.
See #53399.
Built from https://develop.svn.wordpress.org/trunk@51425


git-svn-id: http://core.svn.wordpress.org/trunk@51036 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/post.php

@@ -7437,7 +7437,7 @@ function _publish_post_hook( $post_id ) {
  *
  * @since 3.1.0
  *
- * @param int|WP_Post $post Post ID or post object. Defaults to global $post.
+ * @param int|WP_Post $post Post ID or post object.
  * @return int|false Post parent ID (which can be 0 if there is no parent),
  *                   or false if the post does not exist.
  */

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51423';
+$wp_version = '5.9-alpha-51425';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.