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