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