minor #19393 [Security] fix getUser function link (Enz000)

This PR was submitted for the 7.0 branch but it was squashed and merged into the 6.3 branch instead.

Discussion
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[Security] fix getUser function link

`Symfony\Component\Security\Core\Security` class has been deprecated since 6.2 and deleted in 7.0.

We should use `Symfony\Bundle\SecurityBundle\Security` instead.

Commits
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e2b7dad [Security] fix getUser function link

Author: OskarStark

security.rst

@@ -1097,7 +1097,7 @@ token (or whatever you need to return) and return the JSON response:
 
     The ``#[CurrentUser]`` can only be used in controller arguments to
     retrieve the authenticated user. In services, you would use
-    :method:`Symfony\\Component\\Security\\Core\\Security::getUser`.
+    :method:`Symfony\\Bundle\\SecurityBundle\\Security::getUser`.
 
 That's it! To summarize the process: