Docs: Revert [36268] as the global is indeed used, just via the superglobal.

Fixes #35413.

git-svn-id: https://develop.svn.wordpress.org/trunk@36269 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/post.php

@@ -4858,6 +4858,8 @@ function wp_update_attachment_metadata( $post_id, $data ) {
  *
  * @since 2.1.0
  *
+ * @global string $pagenow
+ *
  * @param int $post_id Optional. Attachment ID. Default 0.
  * @return string|false Attachment URL, otherwise false.
  */