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