Fix syntax highlighting in readme

Author: thecrypticace

README.md

@@ -35,7 +35,7 @@ Then add the plugin to your main `style.css` file:
 
 If you are still using **Tailwind CSS v3**, add the plugin to your `tailwind.config.js` file:
 
-```
+```js
 // tailwind.config.js
 module.exports = {
   theme: {