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