clap 3.0.0-rc.7

We've been iterating on the feedback we've received since 3.0.0-rc.0 and are looking for any additional feedback to help polish this up for the 3.0 release!

The main thing left from the last reddit thread is improving the derive documentation. Would appreciate engaging people more on that Issue so we can better understand use cases and needs to see how to adapt the documentation.

Check out the 3.0.0-rc.7 docs!