message: [Doc] update list usage
diff: @@ -18,7 +18,11 @@ Vue.use(List);
  :finished="finished"
  @load="onLoad"
  >
  - <van-cell v-for="item in list" :key="item" :title="item + ''" />
  + <van-cell
  + v-for="item in list"
  + :key="item"
  + :title="item"
  + />
  </van-list>
  ```
  