Use new line for unsetting variable

MD_STD_SEC.php

@@ -38,7 +38,8 @@ public static function validateAntiCsrfToken():bool {
         ) {
             $validity = true;
         }
-        $_SESSION['csrf-token'] = null; unset($_SESSION['csrf-token']);
+        $_SESSION['csrf-token'] = null;
+        unset($_SESSION['csrf-token']);
 
         return $validity;