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