[docs] Headings should be linkable

[atomiks]

Docs feedback

It's not possible to click headings to link to subsections of a page. Headings should have <a> tags around them with id hashes.

[colmtuite]

You can click the quick nav link

[atomiks]

You can click the quick nav link

I forgot that was possible, doesn't seem easily discoverable + doesn't work on narrow viewports/mobile?

[imMatheus]

Still feel like the headers should be linkable IMO, also, would be fairly easy to add no? I could make a quick PR for it

[mnajdova]

I noticed this and forgot to mention it. The most common use-case for me is to click on the header and share a link with someone. I am already looking at the title, finding it again in the table of content seems like an overkill.