Added namespace for example controller

Author: TheGarious

page_creation.rst

@@ -216,7 +216,9 @@ Make sure that ``LuckyController`` extends Symfony's base
 Now, use the handy ``render()`` function to render a template. Pass it a ``number``
 variable so you can use it in Twig::
 
+    <?php
     // src/Controller/LuckyController.php
+    namespace App\Controller;
 
     // ...
     class LuckyController extends AbstractController