[Form] Add a 'submitted' attribute to the form view

reference/forms/twig_reference.rst

@@ -295,6 +295,9 @@ object:
             <?php echo $view['form']->get('name')->vars['label'] ?>
         </label>
 
+.. versionadded:: 2.4
+    The ``submitted`` variable was added in Symfony 2.4.
+
 +-----------------+-----------------------------------------------------------------------------------------+
 | Variable        | Usage                                                                                   |
 +=================+=========================================================================================+
@@ -310,6 +313,8 @@ object:
 |                 | since this only returns "global" errors: some individual fields may have errors         |
 |                 | Instead, use the ``valid`` option                                                       |
 +-----------------+-----------------------------------------------------------------------------------------+
+| ``submitted``   | Returns ``true`` or ``false`` depending on whether the whole form is submitted          |
++-----------------+-----------------------------------------------------------------------------------------+
 | ``valid``       | Returns ``true`` or ``false`` depending on whether the whole form is valid              |
 +-----------------+-----------------------------------------------------------------------------------------+
 | ``value``       | The value that will be used when rendering (commonly the ``value`` HTML attribute)      |