[HelpHub] Changelogs for Docs managed directly in WordPress

Issue Description

Block editor end user docs has manually added changelog for every new edit on the article. This is very helpful, especially for translators when updating articles in their locales.

First part of this issue is to apply this practice to the rest of documentation managed directly in WordPress - the rest of HelpHub and parts of DevHub (Plugin, Theme, Common APIs Handbooks).

Second part of the issue is that we can expect to come to the point in time when this changelog will be longer than the content itself. We don't want that so we need to think of a better way to do it. Perhaps the quick solution could be placing it on the second page using <!--nextpage--> tag.

Third part of the issue is making everything automated. Before Gutenberg HelpHub had Enhanced Revisions plugin which allowed adding a short message for the update. If something like this can be restored and used on frontend to show dates and messages that could be extremely useful and time saving.

Why is this a problem?

It is unknown when was the last content update and how current it is. Also, this would make life so much easier for locale translators.

Suggested Fix

Let's discuss about possible ways to add changelog wherever needed/possible, how to do it and how to automate it.

Start by reviewing the manually added changelogs in the Block Editor end-user docs, then compare the proposed approaches for HelpHub and DevHub handbooks. Consider the <!--nextpage--> placement and the former Enhanced Revisions plugin. Done means an agreed, workable approach for adding changelogs and automating dates and update messages where appropriate.