Feature request: Navigation overview

[taprobane99]

Folio is great for short notes, but longer ones are tricky to navigate.

Would be nice to have a simple overview - a list of headings from the note. When you click on a heading in the overview it takes you to that section of the main note. Have a look at Typora (View > Outline) for an example of what I mean.

A temporary pop up, like the Markdown Cheetsheet, with the activation icon also in the bottom right corner, would suit Folio's minimalist appearance.

It could disappear once you click on the heading you want to go to.

Probably good to have this feature as an optional "Enable Overview" in Preferences, so users who never use it won't have an extra icon in the UI.

[toolstack]

Not sure this fits in the style for Folio, but I'd probably accept a PR if it was submitted.