In the rich text editor:
@astralArbitrary
In a comment:
[astralArbitrary](https://chowlings.com/user/astralArbitrary)
For Names and Avatars:
In the rich text editor:
%astralArbitrary
In a comment:
[![astralArbitrary's Avatar](https://chowlings.com/images/avatars/609.png?v=1644063313)](https://chowlings.com/user/astralArbitrary) [astralArbitrary](https://chowlings.com/user/astralArbitrary)