Update ast.main function for Python 3.14 (#13982)

Author: donBarbos

stdlib/@tests/stubtest_allowlists/py314.txt

@@ -251,7 +251,6 @@ ast.arg.__annotations_cache__
 ast.arguments.__annotations_cache__
 ast.comprehension.__annotations_cache__
 ast.keyword.__annotations_cache__
-ast.main
 ast.match_case.__annotations_cache__
 ast.withitem.__annotations_cache__
 asyncio.__all__

stdlib/ast.pyi

@@ -7,7 +7,7 @@ from _ast import (
     PyCF_TYPE_COMMENTS as PyCF_TYPE_COMMENTS,
 )
 from _typeshed import ReadableBuffer, Unused
-from collections.abc import Iterable, Iterator
+from collections.abc import Iterable, Iterator, Sequence
 from typing import Any, ClassVar, Generic, Literal, TypedDict, TypeVar as _TypeVar, overload
 from typing_extensions import Self, Unpack, deprecated
 
@@ -2016,4 +2016,9 @@ class NodeTransformer(NodeVisitor):
     #       is also allowed in some cases -- this needs to be mapped.
 
 def unparse(ast_obj: AST) -> str: ...
-def main() -> None: ...
+
+if sys.version_info >= (3, 14):
+    def main(args: Sequence[str] | None = None) -> None: ...
+
+else:
+    def main() -> None: ...