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