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