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