Merge pull request #4037 from nicoddemus/deprecate-item-warnings-captured-hook

Document that item parameter of pytest_warning_captured hook is deprecated

src/_pytest/hookspec.py

@@ -562,6 +562,9 @@ def pytest_warning_captured(warning_message, when, item):
         * ``"runtest"``: during test execution.
 
     :param pytest.Item|None item:
+        **DEPRECATED**: This parameter is incompatible with ``pytest-xdist``, and will always receive ``None``
+        in a future release.
+
         The item being executed if ``when`` is ``"runtest"``, otherwise ``None``.
     """