In the rich text editor:
@cas
In a comment:
[cas](https://chowlings.com/user/cas)
For Names and Avatars:
In the rich text editor:
%cas
In a comment:
[![cas's Avatar](https://chowlings.com/images/avatars/575.png?v=1644063309)](https://chowlings.com/user/cas) [cas](https://chowlings.com/user/cas)