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