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