Hello!

I was wondering if you would consider adding optional sections to the left sidebar?

Currently, I can easily add multiple level of collapsible folders:

root
    /folder A
        /folder AA
             /folder AAA
                 page
    /folder B
    .....

What I would like to do is separating those folders by sections:

root
   Section 1
        /folder A
        /folder AA
             /folder AAA
                 page
         /folder B
   Section 2
         /folder C

Similar to how Storybook is doing it:

But maybe with a look that is more similar to React Spectrum:

One use case that we currently have is for the following Retype website: https://gsoft-inc.github.io/wl-web-configs/ for which at some point we will deprecate tools that we stopped using. We would like to keep the tool documentation but move it to a "Legacy" section at the bottom of the sidebar:

web-configd
    /browserslist
    /eslint
    /stylelint
    .....

   Legacy Section  <---
   /postcss

Another use case, is for our future "hub" website for which we will want to distinguish our backend and frontend documentation sites in the sidebar, something like:

hub
   Backend
       ...
   Frontend
      web-configs (link to https://gsoft-inc.github.io/wl-web-configs/)
      @squide (link to https://gsoft-inc.github.io/wl-squide/)
      ...

Let me know what you think!

Thank you