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