Make pre-commit only check c/h/cpp/hpp files

Clang format does not have a configuration for python, bash, or other
files. So we should really only use it for our C++ and header files.

Bug: b/187094215
Change-Id: I7886c7b1d71e69b09364cd7f456dc34c73ecc8fc

pre-commit

diff --git a/pre-commit b/pre-commit
index b083f5b..d694756 100755
--- a/pre-commit
+++ b/pre-commit
@@ -10,9 +10,9 @@
 TMPDIR=$(mktemp -d -t gcp-$(date +%Y-%m-%d-%H-%M-%S)-XXXXXXXXXX)
 diffFile=$(mktemp gpc-XXXXXXXXX --tmpdir=$TMPDIR)
 
-# Get every file that's been added, changed, or modified in the current index
-# except for shell scripts.
-FILES=$(git diff --cached --name-only --diff-filter=ACM | grep -v '\.sh')
+# Get every source file that's been added, changed, or modified in the
+# current index.
+FILES=$(git diff --cached --name-only --diff-filter=ACM | grep '\.cpp$\|\.hpp$\|\.h$\|\.c$')
 
 # Checkout a copy of current index into TMPDIR. This is necessary so that we
 # only read the versions of files that are being committed, and not any changes