Actually, I'm convinced `Vagrantfile`'s is better strictly on the merit of github's syntax highlighting recognition:
https://github.com/myplanetdigital/vagrant-ariadne/blob/master/Vagrantfile
https://github.com/myplanetdigital/vagrant-ariadne/blob/master/Cheffile

Tons of `linguist` issues related to this, but seems like it's a longstanding problem with many different solutions and little consensus: https://github.com/github/linguist/search?q=shebang