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