In the rich text editor:
@Stiigma
In a comment:
[Stiigma](https://chowlings.com/user/Stiigma)
For Names and Avatars:
In the rich text editor:
%Stiigma
In a comment:
[](https://chowlings.com/user/Stiigma) [Stiigma](https://chowlings.com/user/Stiigma)