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