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

stdlib/zoneinfo/__init__.pyi

@@ -21,7 +21,7 @@ if sys.version_info >= (3, 9):
     class ZoneInfo(tzinfo):
         @property
         def key(self) -> str: ...
-        def __init__(self, key: str) -> None: ...
+        def __new__(cls, key: str) -> Self: ...
         @classmethod
         def no_cache(cls, key: str) -> Self: ...
         @classmethod