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