update: add weui-active to demo index

Author: JuneAndGreen

tools/demo/example/index.wxml

@@ -14,7 +14,7 @@
  <view class="kind-list__item-bd {{item.open ? 'kind-list__item-bd_show' : ''}}">
  <view class="weui-cells {{item.open ? 'weui-cells_show' : ''}}">
  <block wx:for="{{item.pages}}" wx:for-item="page" wx:key="*this">
- <navigator url="{{page}}/{{page}}" class="weui-cell weui-cell_access" hover-class="weui-cell_active">
+ <navigator url="{{page}}/{{page}}" class="weui-cell weui-cell_access" hover-class="weui-cell_active weui-active">
  <view class="weui-cell__bd">{{page}}</view>
  <view class="weui-cell__ft weui-cell__ft_in-access"></view>
  </navigator>