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