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