In the rich text editor:
@Raibread403
In a comment:
[Raibread403](https://chowlings.com/user/Raibread403)
For Names and Avatars:
In the rich text editor:
%Raibread403
In a comment:
[![Raibread403's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Raibread403) [Raibread403](https://chowlings.com/user/Raibread403)