docs: add ids and links to each section header

[LuLaValva]

Most documentation sites (including GitHub .md display, HackMD, every web framework documentation I could find) include links next to each header with # hrefs that point to the header itself. This is a useful feature for sharing specific parts of the documentation and it is (in my opinion) a must-have for support.

• Example on react.dev

It has also been suggested that this feature is built alongside a "table of contents" for each page.