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