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