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