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