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