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