Shortlinks

A way of referencing URLs without typing out the full domain.
Common shorthands for websites are mutually agreed upon.
Commonly:
- gh/[user]/[repo]#[issue] links to https://github.com/[user]/[repo]/issues/[issue]: repo and issue are omittable in the case that only a user or only a repository are wanted to be linked to.
- Same for gl but to GitLab instead of GitHub.
- Same for gd but to GitDab.
- tw/[user] links to https://twitter.com/[user].
- sw/[id] links to https://steamcommunity.com/sharedfiles/filedetails/?id=[id].
References to the [Agora] could also be made shortlinks, perhaps ag/[node]?
Shortlinks aim to emulate the automatic link replacements of the website in question.
- gh/[content] should behave the same as if [content] was posted on GitHub itself.
- tw/[user] should replace the functionality of mentioning @user on Twitter.