In the rich text editor:
@retro-r0t
In a comment:
[retro-r0t](https://chowlings.com/user/retro-r0t)
For Names and Avatars:
In the rich text editor:
%retro-r0t
In a comment:
[![retro-r0t's Avatar](https://chowlings.com/images/avatars/832.png?v=1644063332)](https://chowlings.com/user/retro-r0t) [retro-r0t](https://chowlings.com/user/retro-r0t)