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