Handbooks: warn if user is modifying page and causing status change from published to pending

[sippis]

Everyone does not have permission to publish handbook pages, even tho they have permission to edit and save all the pages. Users without publishing permissions do modify the pages and save it - which causes the page status to change from published to pending. This results on rare occasions published pages to disappear from handbooks.

We should warn users if they are editing page which is going to revert from published to pending.

[coffee2code]

#4521 was marked as a duplicate.

[coffee2code]

Pertinent comment by dd32 from #4521:

Apparently when someone who doesn't have publish_posts edits the publish'd documents the post reverts to pending.

It somewhat sounds like a user-role has edit_published_posts but not publish_posts and causes that..

My thought is that the handbook pages should remain published if a non-privledged user edits them, but others have informed me that ideally it'd not make their edits public until review (which seems to be what's happening now).

First step seems to be to trust users who have edit access, and keep the pages published. Second step sounds like it's to add an editorial plugin that lets you put future changes into a review queue.

[ocean90]

Related upstream issue: ​https://github.com/WordPress/gutenberg/issues/23119