docsify-sidebarfooter

Add a footer notice for Docsify.js

https://cdnjs.webstatic.cn/ajax/libs/docsify-sidebarfooter/5.0.7/docsify-sidebar.js
https://cdnjs.webstatic.cn/ajax/libs/docsify-sidebarfooter/5.0.7/docsify-sidebar.min.js