Docs: Add a missing return description for the deprecated get_screen_icon() function.

See #41017.

Built from https://develop.svn.wordpress.org/trunk@41275


git-svn-id: http://core.svn.wordpress.org/trunk@41115 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/deprecated.php

@@ -1233,7 +1233,7 @@ function screen_icon() {
  * @since 3.2.0
  * @deprecated 3.8.0
  *
- * @return string
+ * @return string An HTML comment explaining that icons are no longer used.
  */
 function get_screen_icon() {
 	_deprecated_function( __FUNCTION__, '3.8.0' );