Publish all symbols on page before page can be published

It would be great to have a way to ensure that symbols on a page are all published before the page itself can be published, so that the page isn’t missing anything when it goes live.

This could appear as a warning message ("This page has unpublished symbols - do you still want to publish?"), with options for a) still publishing the page without publishing the symbols, b) publishing the page and also publishing all of the corresponding symbols, or c) canceling.