FIX 12.8.md

n declared and not used

eBook/12.8.md

@@ -93,7 +93,7 @@ func main() {
 			return
 		}
 		outputString := string(inputString[2:5]) + "\r\n"
-		n, err := outputWriter.WriteString(outputString)
+		_, err := outputWriter.WriteString(outputString)
 		if err != nil {
 			fmt.Println(err)
 			return