[HttpFoundation] Added RFC reference to 308

Author: lyrixx

src/Symfony/Component/HttpFoundation/Response.php

@@ -83,7 +83,7 @@ class Response
  305 => 'Use Proxy',
  306 => 'Reserved',
  307 => 'Temporary Redirect',
- 308 => 'Permanent Redirect',
+ 308 => 'Permanent Redirect', // RFC-reschke-http-status-308-07
  400 => 'Bad Request',
  401 => 'Unauthorized',
  402 => 'Payment Required',