In the rich text editor:
@Toasti
In a comment:
[Toasti](https://chowlings.com/user/Toasti)
For Names and Avatars:
In the rich text editor:
%Toasti
In a comment:
[![Toasti's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Toasti) [Toasti](https://chowlings.com/user/Toasti)