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