Remove unused TypeVar (#7079)

Flagged by PyCQA/flake8-pyi#161

Author: AlexWaygood

stdlib/zoneinfo/__init__.pyi

@@ -1,10 +1,7 @@
-import typing
 from _typeshed import Self, StrPath
 from datetime import tzinfo
 from typing import Any, Iterable, Protocol, Sequence
 
-_T = typing.TypeVar("_T", bound=ZoneInfo)
-
 class _IOBytes(Protocol):
     def read(self, __size: int) -> bytes: ...
     def seek(self, __size: int, __whence: int = ...) -> Any: ...