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