fix the __init__ of several C-classes (#13211)

stdlib/datetime.pyi

@@ -29,7 +29,7 @@ class timezone(tzinfo):
     utc: ClassVar[timezone]
     min: ClassVar[timezone]
     max: ClassVar[timezone]
-    def __init__(self, offset: timedelta, name: str = ...) -> None: ...
+    def __new__(cls, offset: timedelta, name: str = ...) -> Self: ...
     def tzname(self, dt: datetime | None, /) -> str: ...
     def utcoffset(self, dt: datetime | None, /) -> timedelta: ...
     def dst(self, dt: datetime | None, /) -> None: ...