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