fix black formatting of standalone programs

Black will only check .py files when given a dir and --check, so list
our few standalone programs explicitly.  This causes the repo launcher
to be reformatted since it was missed in the previous mass reformat.

Bug: b/267675342
Change-Id: Ic90a7f5d84fc02e9fccb05945310fd067e2ed764
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/385034
Tested-by: Mike Frysinger <vapier@google.com>
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Mike Frysinger <vapier@google.com>

run_tests

@@ -27,8 +27,16 @@ ROOT_DIR = os.path.dirname(os.path.realpath(__file__))
 
 def run_black():
     """Returns the exit code from black."""
+    # Black by default only matches .py files.  We have to list standalone
+    # scripts manually.
+    extra_programs = [
+        "repo",
+        "run_tests",
+        "release/update-manpages",
+    ]
     return subprocess.run(
-        [sys.executable, "-m", "black", "--check", ROOT_DIR], check=False
+        [sys.executable, "-m", "black", "--check", ROOT_DIR] + extra_programs,
+        check=False,
     ).returncode