Persisting : forget a "use" statement ?

The `ProductController` created above (L332) by `$ php bin/console make:controller ProductController` use this generated code :
```php
    return $this->render('product/index.html.twig', [
      'controller_name' => 'ProductController',
    ]);
```

But we modify this to returns a `new Response('...')`, so we must add a `use Symfony\Component\HttpFoundation\Response;` statement to work.

Not sure if it's better to force good habits of "search and debug", or just having a "cut n' paste" working example (-:

Author: Rom1deTroyes

doctrine.rst

@@ -340,6 +340,8 @@ and save it!
     namespace App\Controller;
 
     // ...
+    use Symfony\Component\HttpFoundation\Response;
+    
     use App\Entity\Product;
 
     class ProductController extends AbstractController