tweak stdlib imports to follow Google style guide

Google Python style guide says to import modules.
Clean up all our stdlib imports.  Leave the repo ones alone
for now as that's a much bigger shave.

Change-Id: Ida42fc2ae78b86e6b7a6cbc98f94ca04b295f8cc
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/383714
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Mike Frysinger <vapier@google.com>
Tested-by: Mike Frysinger <vapier@google.com>

release/update_manpages.py

@@ -18,8 +18,8 @@ Most code lives in this module so it can be unittested.
 """
 
 from pathlib import Path
-from functools import partial
 import argparse
+import functools
 import multiprocessing
 import os
 import re
@@ -112,7 +112,9 @@ def main(argv):
 
         # Run all cmd in parallel, and wait for them to finish.
         with multiprocessing.Pool() as pool:
-            pool.map(partial(worker, cwd=tempdir, check=True), cmdlist)
+            pool.map(
+                functools.partial(worker, cwd=tempdir, check=True), cmdlist
+            )
 
     for tmp_path in MANDIR.glob("*.1.tmp"):
         path = tmp_path.parent / tmp_path.stem