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