[DomCrawler] Add hint about Form::getName method

Author: JustBlackBird

components/dom_crawler.rst

@@ -478,6 +478,8 @@ useful methods for working with forms::
 
     $method = $form->getMethod();
 
+    $name = $form->getName();
+
 The :method:`Symfony\\Component\\DomCrawler\\Form::getUri` method does more
 than just return the ``action`` attribute of the form. If the form method
 is GET, then it mimics the browser's behavior and returns the ``action``

testing.rst

@@ -801,6 +801,12 @@ their type::
     $form['my_form[field][O]']->upload('/path/to/lucas.jpg');
     $form['my_form[field][1]']->upload('/path/to/lisa.jpg');
 
+.. tip::
+
+    All field names in forms generated by symfony are prefixed with form's name.
+    If the name is autogenerated you can get it using
+    :method:`Symfony\\Component\\DomCrawler\\Form::getName` method.
+
 .. tip::
 
     If you purposefully want to select "invalid" select/radio values, see