minor #15389 Adding FQCN (ThomasLandauer)

This PR was merged into the 4.4 branch.

Discussion
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Adding FQCN

Commits
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181684a Adding FQCN

Author: javiereguiluz

reference/configuration/framework.rst

@@ -1383,7 +1383,7 @@ The possible values for this option are:
 
 * ``null``, use it to disable this protection. Same behavior as in older Symfony
   versions.
-* ``'none'`` (or the ``Cookie::SAMESITE_NONE`` constant), use it to allow
+* ``'none'`` (or the ``Symfony\Component\HttpFoundation\Cookie::SAMESITE_NONE`` constant), use it to allow
   sending of cookies when the HTTP request originated from a different domain
   (previously this was the default behavior of null, but in newer browsers ``'lax'``
   would be applied when the header has not been set)