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