message: support hooks: ignore submodules for single file format check
diff: @@ -57,7 +57,7 @@ do
  # `$CLANG_FORMAT` and `$BUILDIFY` are defined, or that the default values it
  # assumes for these variables correspond to real binaries on the system. If
  # either of these things aren't true, the check fails.
  - for i in $(git diff --name-only $RANGE --diff-filter=ACMR 2>&1); do
  + for i in $(git diff --name-only $RANGE --diff-filter=ACMR --ignore-submodules=all 2>&1); do
  echo -ne " Checking format for $i - "
  "$SCRIPT_DIR"/check_format.py check $i
  if [[ $? -ne 0 ]]; then
  