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