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