[Added] username_error_regex to en_web_folder_user.lng

Author: Alex Wink

interface/web/sites/lib/lang/en_web_folder_user.lng

@@ -11,4 +11,5 @@ $wb['password_mismatch_txt'] = 'The passwords do not match.';
 $wb['password_match_txt'] = 'The passwords do match.';
 $wb["no_folder_perm"] = 'You have no permission for this folder.';
 $wb['error_user_exists_already_txt'] = 'There is already a record for this user.';
+$wb["username_error_regex"] = 'The Username contains invalid characters.';
 ?>