In the rich text editor:
@Bittebr1
In a comment:
[Bittebr1](https://chowlings.com/user/Bittebr1)
For Names and Avatars:
In the rich text editor:
%Bittebr1
In a comment:
[![Bittebr1's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Bittebr1) [Bittebr1](https://chowlings.com/user/Bittebr1)