[#10022] fix a minor typo

Author: xabbuh

reference/forms/twig_reference.rst

@@ -227,7 +227,7 @@ This test will check if the current ``form`` does not have a parent form view.
 .. code-block:: twig
 
     {# DON'T DO THIS: this simple check can't differentiate between a form having
-       a parent form view and a form defining a normal form field called 'parent' #}
+       a parent form view and a form defining a nested form field called 'parent' #}
 
     {% if form.parent is null %}
         {{ form_errors(form) }}

reference/twig_reference.rst

@@ -756,6 +756,8 @@ rootform
 .. code-block:: twig
 
     {% if form is rootform %}
+        {# ... #}
+    {% endif %}
 
 ``form``
     **type**: ``FormView``