minor #14939 Clarify the role of http_method_override (nicolas-grekas)

This PR was merged into the 4.4 branch.

Discussion
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Clarify the role of http_method_override

See also symfony/recipes#892

Commits
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91ecbda Clarify the role of http_method_override

Author: OskarStark

forms.rst

@@ -777,7 +777,8 @@ to the ``form()`` or the ``form_start()`` helper functions:
     that stores this method. The form will be submitted in a normal ``POST``
     request, but :doc:`Symfony's routing </routing>` is capable of detecting the
     ``_method`` parameter and will interpret it as a ``PUT``, ``PATCH`` or
-    ``DELETE`` request. See the :ref:`configuration-framework-http_method_override` option.
+    ``DELETE`` request. The :ref:`configuration-framework-http_method_override`
+    option must be enabled for this to work.
 
 Changing the Form Name
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