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