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