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