In the rich text editor:
@H0usekey
In a comment:
[H0usekey](https://chowlings.com/user/H0usekey)
For Names and Avatars:
In the rich text editor:
%H0usekey
In a comment:
[](https://chowlings.com/user/H0usekey) [H0usekey](https://chowlings.com/user/H0usekey)