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