In the rich text editor:
@Niuhi
In a comment:
[Niuhi](https://chowlings.com/user/Niuhi)
For Names and Avatars:
In the rich text editor:
%Niuhi
In a comment:
[](https://chowlings.com/user/Niuhi) [Niuhi](https://chowlings.com/user/Niuhi)