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