doc: format general markdown files

Use `make format-md` to format general markdown files.

PR-URL: https://github.com/nodejs/node/pull/40322


Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Zijian Liu <lxxyxzj@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>