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