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