[ticket/12458] Apply Squiz.WhiteSpace.SuperfluousWhitespace.* to legacy code.

* There MUST NOT be trailing whitespace at the end of lines.
* There MUST NOT be whitespace before the first content of a file.
* There MUST NOT be whitespace after the last content of a file.
* Functions MUST NOT contain multiple empty lines in a row.

PHPBB3-12458

phpBB/includes/ucp/ucp_notifications.php

@@ -99,7 +99,7 @@ class ucp_notifications
 
 						meta_refresh(3, $this->u_action);
 						$message = $user->lang['NOTIFICATIONS_MARK_ALL_READ_SUCCESS'];
-						
+
 						if ($request->is_ajax())
 						{
 							$json_response = new \phpbb\json_response();