minor symfony#21260 [Routing] minor symfony#21259 add missing use in code example (Asenar)

This PR was merged into the 7.3 branch.

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[Routing] minor symfony#21259 add missing use in code example

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75cc145 minor symfony#21259 add missing use in code example

Author: javiereguiluz

routing.rst

@@ -1559,6 +1559,7 @@ This way, the ``product_show`` alias could be deprecated.
         namespace App\Controller;
 
         use Symfony\Component\HttpFoundation\Response;
+        use Symfony\Component\Routing\Attribute\DeprecatedAlias;
         use Symfony\Component\Routing\Attribute\Route;
 
         class ProductController