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