[clang-tidy] Support for negative convention

Hello David,

You can create your own checker to do that. It’s really not very complicated for a simple naming convention like this one. You may want to look at https://www.youtube.com/watch?v=WwViXLNPGkY, it’s a talk (in French, but I know it’s not an issue for you) about this subject that was given during a meetup not long ago.