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