minor #20778 [Serializer] Fix namespace (HypeMC)

This PR was merged into the 6.4 branch.

Discussion
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[Serializer] Fix namespace

I messed up in #20776. Somehow I misread the namespace for a use statement. The original was correct.
Sorry about this 😞

Commits
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d0a17c5 [Serializer] Fix namespace

Author: javiereguiluz

serializer.rst

@@ -1421,7 +1421,7 @@ like:
     .. code-block:: php
 
         // config/services.php
-        namespace Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
+        namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 
         use Symfony\Component\Serializer\Normalizer\CustomNormalizer;