fix issue 8447 doc

Author: ericluoliu

changelog/8447.deprecation.rst

@@ -1,4 +1,4 @@
-Defining a custom pytest node type which is both an :class:`pytest.Item <Item>` and a :class:pytest.Collector <Collector>` now issues a warning.
+Defining a custom pytest node type which is both an :class:`pytest.Item <Item>` and a :class:`pytest.Collector <Collector>` now issues a warning.
 It was never sanely supported and triggers hard to debug errors.
 
 Instead, a separate collector node should be used, which collects the item. See :ref:`non-python tests` for an example.