minor #9981 Update scheme.rst (deprecated SensioFrameworkExtraBundle's routing annotations) (royklutman)

This PR was submitted for the 2.8 branch but it was merged into the 3.4 branch instead (closes #9981).

Discussion
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Update scheme.rst (deprecated SensioFrameworkExtraBundle's routing annotations)

Updated because SensioFrameworkExtraBundle's routing annotations have been deprecated.

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Commits
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b7470b9 Update scheme.rst

Author: javiereguiluz

routing/scheme.rst

@@ -16,7 +16,7 @@ the URI scheme via schemes:
         namespace AppBundle\Controller;
 
         use Symfony\Bundle\FrameworkBundle\Controller\Controller;
-        use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
+        use Symfony\Component\Routing\Annotation\Route;
 
         class MainController extends Controller
         {