[Form] Fix more broken references related to removed pages

best_practices.rst

@@ -303,7 +303,7 @@ to add buttons in the templates. This also improves the separation of concerns
 because the button styling (CSS class and other attributes) is defined in the
 template instead of in a PHP class.
 
-However, if you create a :doc:`form with multiple submit buttons </form/multiple_buttons>`
+However, if you create a :ref:`form with multiple submit buttons <processing-forms-multiple-buttons>`
 you should define them in the controller instead of the template. Otherwise, you
 won't be able to check which button was clicked when handling the form in the controller.
 

components/form.rst

@@ -77,7 +77,7 @@ object to read data off of the correct PHP superglobals (i.e. ``$_POST`` or
 
     If you need more control over exactly when your form is submitted or which
     data is passed to it,
-    :doc:`use the submit() method to handle form submissions </form/direct_submit>`.
+    :ref:`use the submit() method to handle form submissions <processing-forms-submit-method>`.
 
 .. sidebar:: Integration with the HttpFoundation Component
 

form/validation_groups.rst

@@ -42,7 +42,7 @@ other group, add the special ``Default`` group::
 Choosing Validation Groups Based on the Clicked Button
 ------------------------------------------------------
 
-When your form has :doc:`multiple submit buttons </form/multiple_buttons>`, you
+When your form has :ref:`multiple submit buttons <processing-forms-multiple-buttons>`, you
 can change the validation group based on the clicked button. For example, in a
 multi-step form like the following, you might want to skip validation when
 returning to a previous step::

reference/forms/types/submit.rst

@@ -16,7 +16,7 @@ A submit button.
 The Submit button has an additional method
 :method:`Symfony\\Component\\Form\\ClickableInterface::isClicked` that lets
 you check whether this button was used to submit the form. This is especially
-useful when :doc:`a form has multiple submit buttons </form/multiple_buttons>`::
+useful when :ref:`a form has multiple submit buttons <processing-forms-multiple-buttons>`::
 
     if ($form->get('save')->isClicked()) {
         // ...