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