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