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