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