Update sys.exit and SystemExit.code to have the same types (#8554)

Author: Kevin Kirsche

stdlib/builtins.pyi

@@ -1279,7 +1279,7 @@ else:
         __locals: Mapping[str, object] | None = ...,
     ) -> None: ...
 
-def exit(code: object = ...) -> NoReturn: ...
+def exit(code: sys._ExitCode = ...) -> NoReturn: ...
 
 class filter(Iterator[_T], Generic[_T]):
     @overload
@@ -1616,7 +1616,7 @@ else:
     @overload
     def pow(__base: _SupportsSomeKindOfPow, __exp: complex, __mod: None = ...) -> complex: ...
 
-def quit(code: object = ...) -> NoReturn: ...
+def quit(code: sys._ExitCode = ...) -> NoReturn: ...
 
 class reversed(Iterator[_T], Generic[_T]):
     @overload
@@ -1794,7 +1794,7 @@ class GeneratorExit(BaseException): ...
 class KeyboardInterrupt(BaseException): ...
 
 class SystemExit(BaseException):
-    code: int
+    code: sys._ExitCode
 
 class Exception(BaseException): ...
 

stdlib/sys.pyi

@@ -11,6 +11,8 @@ from typing_extensions import Literal, TypeAlias, final
 
 _T = TypeVar("_T")
 
+# see https://github.com/python/typeshed/issues/8513#issue-1333671093 for the rationale behind this alias
+_ExitCode: TypeAlias = str | int | None
 _OptExcInfo: TypeAlias = OptExcInfo  # noqa: Y047  # TODO: obsolete, remove fall 2022 or later
 
 # Intentionally omits one deprecated and one optional method of `importlib.abc.MetaPathFinder`
@@ -221,8 +223,7 @@ def exc_info() -> OptExcInfo: ...
 if sys.version_info >= (3, 11):
     def exception() -> BaseException | None: ...
 
-# sys.exit() accepts an optional argument of anything printable
-def exit(__status: object = ...) -> NoReturn: ...
+def exit(__status: _ExitCode = ...) -> NoReturn: ...
 def getallocatedblocks() -> int: ...
 def getdefaultencoding() -> str: ...