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