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