Djot language support

[Omikhleia]

Djot (https://djot.net/) is John MacFarlane's experimental "light markup syntax", derived from commonmark, but fixing most of the complex syntax pitfalls, yet with more flexibility on some aspects (e.g. attributes everywhere!)

It has an experimental Lua implementation (https://github.com/jgm/djot.lua).

It sounds pretty cool:
A real quick attempt this week-end shows that its use is quite straightforward (reusing most of the commands for Markdown processing), so I might push it here at some point (after some cleanup and experimentation, and adding to the quick experiment some of the important missing bits, e.g. tables!)