Removed unnecessary code from githook

Author: squidfunk

.githooks/pre-commit

@@ -57,8 +57,7 @@ git diff > "${PATCH}"
 git checkout -- .
 
 # Filter staged files and create short list for files to lint
-STAGE=$(git diff --cached --name-only --diff-filter=ACMR)
-FILES=$(echo ${STAGE} | grep --include=*.js "")
+FILES=$(git diff --cached --name-only --diff-filter=ACMR | grep "\.js$")
 
 # Run linter if the commit contains files that require it
 if [ "$FILES" ]; then