Add OrderedDict.__(r)or__ (#10770)

Author: AlexWaygood

stdlib/collections/__init__.pyi

@@ -373,6 +373,15 @@ class OrderedDict(dict[_KT, _VT], Reversible[_KT], Generic[_KT, _VT]):
     @overload
     def setdefault(self, key: _KT, default: _VT) -> _VT: ...
     def __eq__(self, __value: object) -> bool: ...
+    if sys.version_info >= (3, 9):
+        @overload
+        def __or__(self, __value: dict[_KT, _VT]) -> Self: ...
+        @overload
+        def __or__(self, __value: dict[_T1, _T2]) -> OrderedDict[_KT | _T1, _VT | _T2]: ...
+        @overload
+        def __ror__(self, __value: dict[_KT, _VT]) -> Self: ...
+        @overload
+        def __ror__(self, __value: dict[_T1, _T2]) -> OrderedDict[_KT | _T1, _VT | _T2]: ...  # type: ignore[misc]
 
 class defaultdict(dict[_KT, _VT], Generic[_KT, _VT]):
     default_factory: Callable[[], _VT] | None