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