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