message: docs(quickstart): update cdn guide
diff: @@ -93,23 +93,25 @@ Vue.use(Vant);
  ### 4. CDN
  +The easiest way to use Vant is to include a CDN link in the html file, after which you can access all components via the global variable `vant`.
  +
  ```html
  <!-- import style -->
  -<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/vant@2.2/lib/index.css" />
  +<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/vant@2.2/lib/index.css">
  <!-- import script -->
  <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.min.js"></script>
  <script src="https://cdn.jsdelivr.net/npm/vant@2.2/lib/vant.min.js"></script>
  <script>
  -var Vue = window.Vue;
  -var vant = window.vant;
  -
  -// Register Lazyload component
  -Vue.use(vant.Lazyload);
  -
  -// Call function components
  -vant.Toast('message');
  + // Render the Button component
  + new Vue({
  + el: '#app',
  + template: `<van-button>Button</van-button>`
  + });
  +
  + // Call function component
  + vant.Toast('Message');
  </script>
  ```
  