Update routing.rst

Author: DurandSacha

routing.rst

@@ -1971,6 +1971,9 @@ This information can be configured per command too::
     // src/Command/SomeCommand.php
     namespace App\Command;
 
+    use Symfony\Component\Console\Command\Command;
+    use Symfony\Component\Console\Input\InputInterface;
+    use Symfony\Component\Console\Output\OutputInterface;
     use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
     use Symfony\Component\Routing\RouterInterface;
     // ...