In the rich text editor:
@Kitsune0304
In a comment:
[Kitsune0304](https://chowlings.com/user/Kitsune0304)
For Names and Avatars:
In the rich text editor:
%Kitsune0304
In a comment:
[![Kitsune0304's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Kitsune0304) [Kitsune0304](https://chowlings.com/user/Kitsune0304)