扩展页和其他4个 tab 页面没有关联呀，扩展页搞独立可以，至少给个跳主页的地方吧？

  {
    "pagePath": "page/component/index",
       "iconPath": "@iconPathComponent",
       "selectedIconPath": "@selectedIconPathComponent",
       "text": "组件"
     },
     {
       "pagePath": "page/animation/index",
       "iconPath": "@iconPathComponent",
       "selectedIconPath": "@selectedIconPathComponent",
       "text": "交互动画"
     },
     {
       "pagePath": "page/API/index",
       "iconPath": "@iconPathAPI",
       "selectedIconPath": "@selectedIconPathAPI",
       "text": "接口"
     },
     {
       "pagePath": "page/cloud/index",
       "iconPath": "@iconPathCloud",
       "selectedIconPath": "@selectedIconPathCloud",
       "text": "云开发"
     }

小程序示例的主页是上面4个tabBar页面，还有一个小程序扩展能力展示页面 在 page/extend
/index 里，这个页面进去后就找不到回主页的入口，也找不到去4个tabBar页面的入口。而在小程序示例的主页或4个tabBar页面上也找不到去 page/extend/index 页面的入口
【建议在 page/extend/index 页面 导航标题左边加个回首页的图标功能】

Start with page/extend/index and the tabBar entries for page/component/index, page/animation/index, page/API/index, and page/cloud/index. Check how navigation is configured in the mini-program example and add an accessible route between the extension page and the four tabBar pages. Done means users can return to the home or tabBar pages from the extension page and reach the extension page from the main example navigation.