In the rich text editor:
@FidgetAttack
In a comment:
[FidgetAttack](https://chowlings.com/user/FidgetAttack)
For Names and Avatars:
In the rich text editor:
%FidgetAttack
In a comment:
[](https://chowlings.com/user/FidgetAttack) [FidgetAttack](https://chowlings.com/user/FidgetAttack)