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