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