message: [Doc] Collapse: update demo
diff: @@ -10,6 +10,7 @@ Vue.use(Collapse).use(CollapseItem);
  ### Usage
  #### Basic Usage
  +
  Use `v-model` to control the name of active panels
  ```html
  @@ -31,6 +32,7 @@ export default {
  ```
  #### Accordion
  +
  In accordion mode, only one panel can be expanded at the same time.
  ```html
  @@ -69,8 +71,6 @@ export default {
  </van-collapse>
  ```
  -
  -
  ### Collapse Props
  | Attribute | Description | Type | Default |
  