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