[Feature]: Sidebar filtering based on entry in the sidebar

[toonn]

I've been struggling trying to hide some sections from the sidebar using title.regex. AFAICT it's basically an alternative way of filtering an entire file out of the sidebar, but matching on the first heading in the file instead of its path?

I have Nixpkgs lib style reference documentation, the sidebar gets cluttered because of the amount of "Inputs," "Type" and "Examples" headers. I'd like to be able to filter them out.

[NotAShelf]

Makes sense. I've finished most of the critical work that was needing attention, so I'll work on it tomorrow.

[NotAShelf]

Could you take a look at #275? I've just rebased, should be good now.

I'm going to avoid merging the PR until you confirm this is about what you were envisioning.