Docs: Various corrections and improvements to inline docs and docblocks.

See #57840


git-svn-id: https://develop.svn.wordpress.org/trunk@55753 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/plugin.php

@@ -707,6 +707,7 @@ function did_action( $hook_name ) {
  * @param string $version     The version of WordPress that deprecated the hook.
  * @param string $replacement Optional. The hook that should have been used. Default empty.
  * @param string $message     Optional. A message regarding the change. Default empty.
+ * @return mixed The filtered value after all hooked functions are applied to it.
  */
 function apply_filters_deprecated( $hook_name, $args, $version, $replacement = '', $message = '' ) {
 	if ( ! has_filter( $hook_name ) ) {