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