Github markdown

Github's markdown parser adheres to the commonmark spec, and introduces some extensions of it's own.
I believe it uses c hoedown as a parser, but I'm not certain.

Documentation

official docs

https://github.github.com/gfm/

PRs/Issues

The keyword fixes, closes, resolves followed by an ISSUE will automatically close the issue when the PR is merged.

See https://help.github.com/en/github/managing-your-work-on-github/linking-a-pull-request-to-an-issue