In the rich text editor:
@Mreows
In a comment:
[Mreows](https://chowlings.com/user/Mreows)
For Names and Avatars:
In the rich text editor:
%Mreows
In a comment:
[![Mreows's Avatar](https://chowlings.com/images/avatars/2620.png?v=1690618855)](https://chowlings.com/user/Mreows) [Mreows](https://chowlings.com/user/Mreows)