Docs: A host of corrections and improvements to inline documentation.

See #57840


git-svn-id: https://develop.svn.wordpress.org/trunk@55732 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/post.php

@@ -1225,7 +1225,7 @@ function get_page_statuses() {
  * @since 4.9.6
  * @access private
  *
- * @return array
+ * @return string[] Array of privacy request status labels keyed by their status.
  */
 function _wp_privacy_statuses() {
 	return array(