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