[ticket/10605] Add parameter documentation to phpbb_delete_user_pms

PHPBB3-10605

phpBB/includes/functions_privmsgs.php

@@ -1085,6 +1085,10 @@ function delete_pm($user_id, $msg_ids, $folder_id)
 
 /**
 * Delete all PM(s) for a given user and delete the ones without references
+*
+* @param	int		$user_id	ID of the user whose private messages we want to delete
+*
+* @return	boolean		False if there were no pms found, true otherwise.
 */
 function phpbb_delete_user_pms($user_id)
 {