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