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