minor #21573 [Serializer] Fix highlighting (OskarStark)

This PR was merged into the 6.4 branch.

Discussion
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[Serializer] Fix highlighting

<img width="1614" height="276" alt="CleanShot 2025-11-12 at 13 50 52@2x" src="https://github.com/user-attachments/assets/eecde822-8802-4eb5-9977-38f354dbbcc8" />

Commits
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54a2235 Fix highlighting

Author: javiereguiluz

serializer/custom_normalizer.rst

@@ -164,8 +164,8 @@ Improving Performance of Normalizers/Denormalizers
 
     The ``getSupportedTypes()`` method was introduced in Symfony 6.3.
 
-Both :class:Symfony\\Component\\Serializer\\Normalizer\\NormalizerInterface
-and :class:Symfony\\Component\\Serializer\\Normalizer\\DenormalizerInterface
+Both :class:`Symfony\\Component\\Serializer\\Normalizer\\NormalizerInterface`
+and :class:`Symfony\\Component\\Serializer\\Normalizer\\DenormalizerInterface`
 define a ``getSupportedTypes()`` method to declare which types they support and
 whether their ``supports*()`` result can be cached.