Docs: Adjust @return value of parent_dropdown() for consistency with other dropdown functions.

See #48303.

git-svn-id: https://develop.svn.wordpress.org/trunk@47100 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/template.php

@@ -887,7 +887,8 @@ function page_template_dropdown( $default = '', $post_type = 'page' ) {
  * @param int         $level   Optional. Page depth level. Default 0.
  * @param int|WP_Post $post    Post ID or WP_Post object.
  *
- * @return null|false Boolean False if page has no children, otherwise print out html elements.
+ * @return void|false HTML dropdown list of page parents on success,
+ *                    false if the page has no children.
  */
 function parent_dropdown( $default = 0, $parent = 0, $level = 0, $post = null ) {
 	global $wpdb;