diagnostics0 DO NOT EDIT THIS FILE. It's managed by the package manager and your changes will be overridden on any future update to the sudo package.
I would recommend instead running sudo visudo
. This will open up a text editor (probably nano unless you have a different default) and allow you to add whatever configuration snippet you want. Then it will validate it and make sure it works when you try to save it. The file will be written to /etc/sudoer.d/visudo
.