message: [Doc] Toast: fix demo
diff: @@ -36,12 +36,12 @@ Toast.fail('Fail');
  ```js
  Toast({
  - text: 'Custom Icon',
  + message: 'Custom Icon',
  icon: 'like-o'
  });
  Toast({
  - text: 'Custom Image',
  + message: 'Custom Image',
  icon: 'https://img.yzcdn.cn/vant/logo.png'
  });
  ```
  