chore: remove else instead of return/continue (#1502)

As[ Effective Go](https://golang.org/doc/effective_go.html?#if) about `if` said, remove else statement instead of return/continue statement.

render/json.go

@@ -128,10 +128,8 @@ func (r AsciiJSON) Render(w http.ResponseWriter) (err error) {
 
 	var buffer bytes.Buffer
 	for _, r := range string(ret) {
-		cvt := ""
-		if r < 128 {
-			cvt = string(r)
-		} else {
+		cvt := string(r)
+		if r >= 128 {
 			cvt = fmt.Sprintf("\\u%04x", int64(r))
 		}
 		buffer.WriteString(cvt)