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