Update tkinter for 3.14 (#14240)

Author: max-muoto

stdlib/@tests/stubtest_allowlists/py314.txt

@@ -13,7 +13,6 @@ multiprocessing.managers._BaseDictProxy.fromkeys
 multiprocessing.process.BaseProcess.interrupt
 multiprocessing.synchronize.SemLock.locked
 tarfile.TarFile.zstopen
-tkinter.Event.__class_getitem__
 
 # =========================
 # New errors in Python 3.14

stdlib/tkinter/__init__.pyi

@@ -4,7 +4,7 @@ from _typeshed import Incomplete, MaybeNone, StrOrBytesPath
 from collections.abc import Callable, Iterable, Mapping, Sequence
 from tkinter.constants import *
 from tkinter.font import _FontDescription
-from types import TracebackType
+from types import GenericAlias, TracebackType
 from typing import Any, ClassVar, Generic, Literal, NamedTuple, Protocol, TypedDict, TypeVar, overload, type_check_only
 from typing_extensions import TypeAlias, TypeVarTuple, Unpack, deprecated
 
@@ -308,6 +308,8 @@ class Event(Generic[_W_co]):
     type: EventType
     widget: _W_co
     delta: int
+    if sys.version_info >= (3, 14):
+        def __class_getitem__(cls, item: Any, /) -> GenericAlias: ...
 
 def NoDefaultRoot() -> None: ...