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