minor #19902 [HttpCache] Remove SensioFrameworkExtraBundle reference (smnandre)

This PR was submitted for the 7.1 branch but it was merged into the 6.4 branch instead.

Discussion
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[HttpCache] Remove SensioFrameworkExtraBundle reference

I'll do a global check on the repository later :)

Commits
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46bef14 [HttpCache] Remove SensioFrameworkExtraBundle reference

Author: javiereguiluz

http_cache/_expiration-and-validation.rst.inc

@@ -5,10 +5,3 @@
     both worlds. In other words, by using both expiration and validation, you
     can instruct the cache to serve the cached content, while checking back
     at some interval (the expiration) to verify that the content is still valid.
-
-    .. tip::
-
-        You can also define HTTP caching headers for expiration and validation by using
-        annotations. See the `FrameworkExtraBundle documentation`_.
-
-.. _`FrameworkExtraBundle documentation`: https://symfony.com/doc/current/bundles/SensioFrameworkExtraBundle/annotations/cache.html