minor #20010 By default Symfony also loads the routes defined in PHP format (javaDeveloperKid)

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

Discussion
----------

 By default Symfony also loads the routes defined in PHP format

Commits
-------

dbb8dff Update routing.rst

Author: javiereguiluz

routing.rst

@@ -157,7 +157,7 @@ the ``BlogController``:
 
 .. note::
 
-    By default Symfony only loads the routes defined in YAML format. If you
+    By default Symfony only loads the routes defined in YAML and PHP format. If you
     define routes in XML and/or PHP formats, you need to
     :ref:`update the src/Kernel.php file <configuration-formats>`.