Final for distutils constants (#12454)

Co-authored-by: Avasam <samuel.06@hotmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

stdlib/distutils/command/check.pyi

@@ -1,4 +1,4 @@
-from typing import Any, ClassVar, Literal
+from typing import Any, ClassVar, Final, Literal
 from typing_extensions import TypeAlias
 
 from ..cmd import Command
@@ -22,7 +22,7 @@ class SilentReporter(_Reporter):
     ) -> None: ...
     def system_message(self, level, message, *children, **kwargs): ...
 
-HAS_DOCUTILS: bool
+HAS_DOCUTILS: Final[bool]
 
 class check(Command):
     description: str

stdlib/distutils/command/config.pyi

@@ -1,12 +1,12 @@
 from _typeshed import StrOrBytesPath
 from collections.abc import Sequence
 from re import Pattern
-from typing import Any, ClassVar, Literal
+from typing import Any, ClassVar, Final, Literal
 
 from ..ccompiler import CCompiler
 from ..cmd import Command
 
-LANG_EXT: dict[str, str]
+LANG_EXT: Final[dict[str, str]]
 
 class config(Command):
     description: str

stdlib/distutils/command/install.pyi

@@ -1,11 +1,12 @@
 import sys
 from collections.abc import Callable
-from typing import Any, ClassVar, Final
+from typing import Any, ClassVar, Final, Literal
 
 from ..cmd import Command
 
-HAS_USER_SITE: bool
-SCHEME_KEYS: tuple[str, ...]
+HAS_USER_SITE: Final[bool]
+
+SCHEME_KEYS: Final[tuple[Literal["purelib"], Literal["platlib"], Literal["headers"], Literal["scripts"], Literal["data"]]]
 INSTALL_SCHEMES: Final[dict[str, dict[str, str]]]
 
 if sys.version_info < (3, 10):

stdlib/distutils/command/install_lib.pyi

@@ -1,8 +1,8 @@
-from typing import Any, ClassVar
+from typing import Any, ClassVar, Final
 
 from ..cmd import Command
 
-PYTHON_SOURCE_EXTENSION: str
+PYTHON_SOURCE_EXTENSION: Final = ".py"
 
 class install_lib(Command):
     description: str