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