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