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