provide feed of recently updated handbook pages

To lower the barrier even farther for those who'd like to watch for vandalism, I'd love to see a portion or all of the diff available in the feed if possible.

"portion or all of the diff available in the feed" - Recent Changes module does this. Just needs a bit of maintaining love for D6. Might be able to use that module rather than writing your own?

This still seems to be missing https://drupal.org/documentation

There's no reason we can't also have this RSS feed in the header of /documentation page like #1031538: Make drupal.org homepage feed discoverable

It seems there's a function for it in place, but not sure how this is getting used drupalorg_handbook_preprocess_drupalorg_home() in the given site.

/**
 * API function to get recent update information for the documentation pages.
 */
function drupalorg_handbook_get_recent_updates($limit = 50) {