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