fix notes on form_widget_args

flask_admin/model/base.py

@@ -399,7 +399,9 @@ class BaseModelView(BaseView, ActionsMixin):
                     }
                 }
 
-        Note, changing the format of a DateTimeField will require changes to both form_widget_args and form_args::
+        Changing the format of a DateTimeField will require changes to both form_widget_args and form_args.
+		
+        Example::
 
             form_args = dict(
                 start=dict(format='%Y-%m-%d %I:%M %p') # changes how the input is parsed by strptime (12 hour time)