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