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