My hacky variation of this would have been to create a git repository inside the generated html folder. Commit the legacy output. Build the new release and then

My hacky variation of this would have been to create a git repository inside the generated html folder. Commit the legacy output. Build the new release and then you can use git to inspect the changes. Even commit away the irrelevant differences so only the broken deltas are highlighted. Iteratively edit the markdown until git reports no changes.