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