feat: add jotdown for comparison

[dpc]

Djot is a "kind-of-more-strict-Markdown" which is (supposedly) making it faster and easier to parse. I am curious myself how well it performs. If the premise is true, I would expect smaller binary overhead and faster parsing.

[dpc]

Name	Overhead (release)	Build (debug)	Parse (release)	Downloads	Version
null	0 KiB	207ms	0ms	-	-
comrak	573 KiB	7s	1ms		v0.32.0
jotdown	204 KiB	896ms	1ms		v0.7.0
markdown	979 KiB	1s	7ms		v1.0.0-alpha.21
minimad	26 KiB	530ms	1ms		v0.13.1
pulldown-cmark	436 KiB	1s	1ms		v0.12.2

I could use a little slower machine, as everything is 1ms... :D ... Good to have problem, I guess.

Viewing the run's json file, it seems like it has similar times as minimad and pulldown, slightly better than comrak?

[dpc]

For sanity I compared the outputs:

-rw-r--r-- 1 dpc dpc  87K Feb  3 19:03 jotdown
-rw-r--r-- 1 dpc dpc 109K Feb  3 19:03 pulldown

just to make sure the produced output is at least similar.