In the rich text editor:
@2manystripes
In a comment:
[2manystripes](https://chowlings.com/user/2manystripes)
For Names and Avatars:
In the rich text editor:
%2manystripes
In a comment:
[](https://chowlings.com/user/2manystripes) [2manystripes](https://chowlings.com/user/2manystripes)