In the rich text editor:
@foxfetti
In a comment:
[foxfetti](https://painted-relics.com/user/foxfetti)
For Names and Avatars:
In the rich text editor:
%foxfetti
In a comment:
[](https://painted-relics.com/user/foxfetti) [foxfetti](https://painted-relics.com/user/foxfetti)