Fixed #32199 -- Doc'd JSONField in ModelForm field mapping.

docs/topics/forms/modelforms.txt

@@ -101,6 +101,8 @@ Model field                         Form field
 
 :class:`GenericIPAddressField`      :class:`~django.forms.GenericIPAddressField`
 
+:class:`JSONField`                  :class:`~django.forms.JSONField`
+
 :class:`ManyToManyField`            :class:`~django.forms.ModelMultipleChoiceField`
                                     (see below)