Run pycln as a pre-commit hook in CI (#8304)

Author: AlexWaygood

.pre-commit-config.yaml

@@ -1,4 +1,9 @@
 repos:
+  - repo: https://github.com/hadialqattan/pycln
+    rev: v2.0.2 # must match requirements-tests.txt
+    hooks:
+      - id: pycln
+        args: [--all, stubs, stdlib, tests, scripts]
   - repo: https://github.com/psf/black
     rev: 22.6.0 # must match requirements-tests.txt
     hooks:

CONTRIBUTING.md

@@ -29,7 +29,7 @@ it takes a bit longer. For more details, read below.
 Typeshed runs continuous integration (CI) on all pull requests. This means that
 if you file a pull request (PR), our full test suite -- including our linter,
 `flake8` -- is run on your PR. It also means that bots will automatically apply
-changes to your PR (using `black` and `isort`) to fix any formatting issues.
+changes to your PR (using `pycln`, `black` and `isort`) to fix any formatting issues.
 This frees you up to ignore all local setup on your side, focus on the
 code and rely on the CI to fix everything, or point you to the places that
 need fixing.
@@ -82,17 +82,19 @@ terminal to install all non-pytype requirements:
 
 ## Code formatting
 
-The code is formatted using `black` and `isort`.
+The code is formatted using `black` and `isort`. Unused imports are also
+auto-removed using `pycln`.
 
 The repository is equipped with a [`pre-commit.ci`](https://pre-commit.ci/)
 configuration file. This means that you don't *need* to do anything yourself to
 run the code formatters. When you push a commit, a bot will run those for you
 right away and add a commit to your PR.
 
 That being said, if you *want* to run the checks locally when you commit,
-you're free to do so. Either run `black` and `isort` manually...
+you're free to do so. Either run `pycln`, `black` and `isort` manually...
 
 ```
+pycln --all .
 isort .
 black .
 ```

requirements-tests.txt

@@ -9,5 +9,6 @@ flake8-pyi==22.5.1
 # must match .pre-commit-config.yaml
 isort==5.10.1
 tomli==1.2.2
+pycln==2.0.2
 packaging==21.3
 termcolor

stdlib/tokenize.pyi

@@ -1,6 +1,5 @@
 import sys
 from _typeshed import StrOrBytesPath
-from builtins import open as _builtin_open
 from collections.abc import Callable, Generator, Iterable, Sequence
 from re import Pattern
 from token import *

stdlib/unittest/loader.pyi

@@ -1,5 +1,4 @@
 import unittest.case
-import unittest.result
 import unittest.suite
 from collections.abc import Callable, Sequence
 from re import Pattern

stubs/aiofiles/aiofiles/os.pyi

@@ -6,7 +6,9 @@ from os import stat_result
 from typing import Any, overload
 from typing_extensions import TypeAlias
 
-from . import ospath as path
+from . import ospath
+
+path = ospath
 
 _FdOrAnyPath: TypeAlias = int | StrOrBytesPath