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