In the rich text editor:
@sirfluffbutts
In a comment:
[sirfluffbutts](https://chowlings.com/user/sirfluffbutts)
For Names and Avatars:
In the rich text editor:
%sirfluffbutts
In a comment:
[![sirfluffbutts's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/sirfluffbutts) [sirfluffbutts](https://chowlings.com/user/sirfluffbutts)