Issue #1166388 by pillarsdotnet: Fixed Regression: user_mail_tokens() needs docs.

modules/user/user.module

@@ -2709,8 +2709,21 @@ function _user_mail_text($key, $language = NULL, $variables = array(), $replace
 /**
  * Token callback to add unsafe tokens for user mails.
  *
- * @see _user_mail_text()
- * @see user_mail()
+ * This function is used by the token_replace() call at the end of
+ * _user_mail_text() to set up some additional tokens that can be
+ * used in email messages generated by user_mail().
+ *
+ * @param $replacements
+ *   An associative array variable containing mappings from token names to
+ *   values (for use with strtr()).
+ * @param $data
+ *   An associative array of token replacement values. If the 'user' element
+ *   exists, it must contain a user account object with the following
+ *   properties:
+ *   - login: The account login name.
+ *   - pass: The hashed account login password.
+ * @param $options
+ *   Unused parameter required by the token_replace() function.
  */
 function user_mail_tokens(&$replacements, $data, $options) {
   if (isset($data['user'])) {