feat: optional table of contents

[wesleimp]

[begleynk]

Thanks for submitting this Weslei! Could you talk a bit about what your use case is for this feature? Is there a time when you specifically wouldn't want to have the table of contents available?

[wesleimp]

When I have a tiny documentation, where there are two or three subtitles maximum on each page, the page becomes a little polluted. Furthermore, other docs generators gives you this option. I think it’s a good feature and nice to have it as optional. WDYT?