In the rich text editor:
@SweetHaven
In a comment:
[SweetHaven](https://chowlings.com/user/SweetHaven)
For Names and Avatars:
In the rich text editor:
%SweetHaven
In a comment:
[![SweetHaven's Avatar](https://chowlings.com/images/avatars/845.png?v=1645086177)](https://chowlings.com/user/SweetHaven) [SweetHaven](https://chowlings.com/user/SweetHaven)