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