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