title: Symfony 4.0 Translator class not injected to controller
body: <p>I got a problem in new symfony 4.</p>
  
  <pre><code>&lt;?php
  
  namespace App\Controller;
  
  use App\Entity\Flight;
  use Symfony\Component\HttpFoundation\Response;
  use Symfony\Component\Routing\Annotation\Route;
  use Symfony\Bundle\FrameworkBundle\Controller\Controller;
  use App\Form\FlightType;
  use Symfony\Component\Translation\Translator;
  use Symfony\Component\HttpFoundation\Request;
  
  /**
   * Class DefaultController
   * @package App\Controller
   */
  class DefaultController extends Controller
  {
      /**
       * 
       * @Route("/")
       * @Route("/{_locale}/", name="homepage", requirements={"_locale" = "%app.locales%"})
       * 
       * @param Translator $translator
       * @param Request $request
       * 
       * @return \Symfony\Component\HttpFoundation\RedirectResponse|Response
       */
      public function index(Translator $translator, Request $request)
      {
          $translated = $translator-&gt;trans('Symfony is great');
  </code></pre>
  
  <p>Error:
  Controller "App\Controller\DefaultController::index()" requires that you provide a value for the "$translator" argument. Either the argument is nullable and no null value has been provided, no default value has been provided or because there is a non optional argument after this one.</p>
  
  <p>Configs:
  service.yaml</p>
  
  <pre><code>services:    
      _defaults:
          autowire: true    
          autoconfigure: true 
          public: false
  
  ...
  App\Controller\:
      autowire: true       
      resource: '../src/Controller'
      tags: ['controller.service_arguments']
  </code></pre>
  
  <p>translation.yaml</p>
  
  <pre><code>framework:
      default_locale: '%locale%'
      translator:
          paths:
              - '%kernel.project_dir%/translations'
          fallbacks: ['en']    
  </code></pre>
  
  <p>Whats wrong? Manual here:
  <a href="http://symfony.com/doc/current/translation.html" rel="nofollow noreferrer">http://symfony.com/doc/current/translation.html</a></p>