Convert org/repo and org/repo#issue to their GitHub links

Somehow we should figure out how to convert things like bevry/query-engine#24 or bevry/safeps into their full github links and maybe even titles too.

I don’t know if you could use Zapier retro-actively to “scrape” out that data from GitHub and get it into Discourse. Alas, Discourse isn’t available officially for Zapier yet outside of any webhook hack that may be possible (don’t know that it is).

Was hoping there would just be an Discourse event we could write some basic ruby for, or maybe even create a simple Discourse plugin where you specify regex replacements you want to do.

Added https://meta.discourse.org/t/the-github-linkback-plugin/66081?u=balupton

Which is good enough. Still requires the full URLs of issues etc to be posted though…