fix(docs): use sphinx note function (#604)

docs/index.rst

@@ -119,7 +119,7 @@ path of a field class, and the (optional) second item is a dictionary used to co
 The ``widget`` and ``widget_kwargs`` keys in the field config dictionary can be used to configure the widget used in admin,
 the other values will be passed as kwargs to the field's ``__init__()``
 
-Note: Use later evaluated strings instead of direct classes for the field and widget classes:
+.. note:: Use later evaluated strings instead of direct classes for the field and widget classes:
 
 .. code-block:: python
 

docs/testing.rst

@@ -90,8 +90,9 @@ If you want to use override as a context manager or decorator, consider using
     def test_override_context_manager():
         ...
 
-Pytest fixture as function or method parameter (
-NOTE: no import needed as fixture is available globally)
+Pytest fixture as function or method parameter.
+
+.. note:: No import needed as fixture is available globally.
 
 .. code-block:: python