[BrowserKit] fix phpdoc

src/Symfony/Component/BrowserKit/Response.php

@@ -67,7 +67,7 @@ class Response
      * @param string $name  The header name
      * @param string $value The header value
      *
-     * @return string The buil header line
+     * @return string The built header line
      */
     protected function buildHeader($name, $value)
     {