minor #13629 Change "In Symfony 4" to "Since Symfony 4" (BafS)

This PR was merged into the 5.0 branch.

Discussion
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Change "In Symfony 4" to "Since Symfony 4"

Small typo for Symfony 5+

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Commits
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2f89f55 Change "In Symfony 4" to "Since Symfony 4"

Author: javiereguiluz

setup/file_permissions.rst

@@ -2,7 +2,7 @@ Setting up or Fixing File Permissions
 =====================================
 
 In Symfony 3.x, you needed to do some extra work to make sure that your cache directory
-was writable. But that is no longer true! In Symfony 4, everything works automatically:
+was writable. But that is no longer true! Since Symfony 4, everything works automatically:
 
 * In the ``dev`` environment, ``umask()`` is used in ``bin/console`` and ``public/index.php``
   so that any created files are writable by everyone.