Re-export dateutil._common.weekday from dateutil.relativedelta (#9819)

Author: AlexWaygood

stubs/python-dateutil/@tests/test_cases/check_relativedelta.py

@@ -0,0 +1,9 @@
+from __future__ import annotations
+
+from dateutil import relativedelta
+
+
+# An illustrative example for why we re-export dateutil._common.weekday from dateutil.relativedelta in the stub
+class Calendar:
+    def __init__(self, week_start: relativedelta.weekday = relativedelta.MO) -> None:
+        self.week_start = week_start

stubs/python-dateutil/dateutil/relativedelta.pyi

@@ -2,7 +2,8 @@ from datetime import date, datetime, timedelta
 from typing import SupportsFloat, TypeVar, overload
 from typing_extensions import Self, TypeAlias
 
-from ._common import weekday
+# See #9817 for why we reexport this here
+from ._common import weekday as weekday
 
 _DateT = TypeVar("_DateT", date, datetime)
 # Work around attribute and type having the same name.