run gofmt in CI

.github/workflows/go.yml

@@ -25,4 +25,7 @@ jobs:
       run: cd examples && go mod tidy && go build syncat.go
 
     - name: Test
-      run: go test -v 
+      run: | 
+        FMT_ISSUES=$(gofmt -l .)
+        if test -n "$FMT_ISSUES" ;then printf "gofmt found problems:\n$FMT_ISSUES\n";exit 11; fi
+        go test -v 

helpers_test.go

@@ -9,7 +9,7 @@ import (
 
 func getDefs(t *testing.T, filename string, data []byte, highlight_lexer string) *Def {
 	var def *Def
-	syn_dir := "./syntax_files"
+    syn_dir := "./syntax_files"
 
 	var defs []*Def
 	lerr, warnings := ParseSyntaxFiles(syn_dir, &defs)