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