bug #8940 Reworded the note about supressing form validation (javiereguiluz)

This PR was merged into the 2.7 branch.

Discussion
----------

Reworded the note about supressing form validation

This replaces #6461 according to reviewer's comments.

@HeahDude please check if this PR is correct according to your comment here: #6461 (comment)

Commits
-------

cb823f7 Reworded the note about supressing form validation

Author: weaverryan

form/dynamic_form_modification.rst

@@ -710,30 +710,5 @@ code from above to generate the submitted form can be reused.
 Suppressing Form Validation
 ---------------------------
 
-To suppress form validation you can use the ``POST_SUBMIT`` event and prevent
-the :class:`Symfony\\Component\\Form\\Extension\\Validator\\EventListener\\ValidationListener`
-from being called.
-
-The reason for needing to do this is that even if you set ``validation_groups``
-to ``false`` there  are still some integrity checks executed. For example
-an uploaded file will still be checked to see if it is too large and the form
-will still check to see if non-existing fields were submitted. To disable
-all of this, use a listener::
-
-    use Symfony\Component\Form\FormBuilderInterface;
-    use Symfony\Component\Form\FormEvents;
-    use Symfony\Component\Form\FormEvent;
-
-    public function buildForm(FormBuilderInterface $builder, array $options)
-    {
-        $builder->addEventListener(FormEvents::POST_SUBMIT, function (FormEvent $event) {
-            $event->stopPropagation();
-        }, 900); // Always set a higher priority than ValidationListener
-
-        // ...
-    }
-
-.. caution::
-
-    By doing this, you may accidentally disable something more than just form
-    validation, since the ``POST_SUBMIT`` event may have other listeners.
+To suppress form validation, set ``validation_groups`` to ``false`` or an empty
+array.