Recommend to use a plugin for generating "Treeview" for each article in the book

[**gitbook-treeview**](https://github.com/aleen42/gitbook-treeview) is a Gitbook plugin designed for generating structures for articles of a book. As the following picture shown, the main structure of a whole article has been clearly shown before contents, and each title has also been directed to a corresponding part. TypeScript Deep Dive is a large book, which has integrated with Gitbook, and I hope that the plugin can helps to enhance readability. If you like it, I hope you can star my project too, and thanks for your appreciations. As for the picture, it's an article named ["Asynchronous Programming"](https://aleen42.gitbooks.io/personalwiki/content/Programming/JavaScript/async_programming/async_programming.html) in my personal wiki book.