Be more specific in phpdoc (Fixes #3216)

src/Symfony/Bundle/TwigBundle/TwigEngine.php

@@ -17,7 +17,7 @@ use Symfony\Component\Templating\TemplateNameParserInterface;
 use Symfony\Component\HttpFoundation\Response;
 
 /**
- * This engine knows how to render Twig templates.
+ * This engine renders Twig templates.
  *
  * @author Fabien Potencier <fabien@symfony.com>
  */