Use "typing.List" as an annotation

Co-authored-by: Tzu-ping Chung <[email protected]>

Author: DiddiLeija

news/10004.trivial.rst

@@ -0,0 +1 @@
+Annotate ``typing.List`` into ``tools.tox_pip.pip()``

tools/tox_pip.py

@@ -9,8 +9,7 @@
 TOX_PIP_DIR = os.path.join(VIRTUAL_ENV, 'pip')
 
 
-def pip(args):
-    # type: (List[str]) -> None
+def pip(args: List[str]) -> None:
     # First things first, get a recent (stable) version of pip.
     if not os.path.exists(TOX_PIP_DIR):
         subprocess.check_call([sys.executable, '-m', 'pip',