Add dynamic form name

Author: Arkalo2

forms.rst

@@ -950,7 +950,8 @@ the submitted data, those fields will be explicitly set to ``null``.
 Extra fields
 ~~~~~~~~~~~~
 
-All form fields are considered properties of the object but you can inject fields directly into your view without specifying them in the form definition.
+All form fields are considered properties of the object but you can inject 
+fields directly into your view without specifying them in the form definition.
 They can be retrieved via the ``getExtraData`` :class:`Symfony\\Component\\Form\\FormTypeInterface`.
 
 This is a creation user form::
@@ -999,6 +1000,14 @@ Here, the referral code is an extra field injected at view level.
 The field name is composed of form ``user_create`` and the field name ``referralCode``.
 It's automatically generated from the form class name. You can :ref:`override it <changing-the-form-name>`
 
+Or you can use use 
+.. code-block:: html+twig
+    {{ form.vars.full_name ~ '[referralCode]' }} 
+    
+to render the form name dynamically
+
+{{ form.vars.full_name ~ '[description]' }}
+
 You can get the referral code via ``getExtraData``::
 
     $extraData = $form->getExtraData();