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