In the rich text editor:
@ramune
In a comment:
[ramune](https://chowlings.com/user/ramune)
For Names and Avatars:
In the rich text editor:
%ramune
In a comment:
[![ramune's Avatar](https://chowlings.com/images/avatars/238.jpg?v=1644063269)](https://chowlings.com/user/ramune) [ramune](https://chowlings.com/user/ramune)