documented the $url parameter better

src/Symfony/Component/HttpFoundation/RedirectResponse.php

@@ -23,7 +23,8 @@ class RedirectResponse extends Response
     /**
      * Creates a redirect response so that it conforms to the rules defined for a redirect status code.
      *
-     * @param string $url     The URL to redirect to
+     * @param string $url     The URL to redirect to. The URL should be a full URL, with schema etc.,
+     *                        but practically every browser redirects on paths only as well
      * @param int    $status  The status code (302 by default)
      * @param array  $headers The headers (Location is always set to the given URL)
      *