How to handle burying/sorting for image occlusion cards

> Re burying, how frequently do users mix and match the two modes?

I'm not sure how frequently users switch between the two IO modes, unfortunately, but what I can say with good certainty is that "Hide one, guess one" is the more popular mode. So what I would say makes up the main case for having note-type-specific sibling behavior in the context of IO is that users typically will have both IO notes and regular clozes contained within the same deck, and sibling spacing and burying will typically make sense for regular text-based clozes while for IO notes, assuming "Hide one, guess one", it won't (and given IOE's multiple-note implementation, no spacing and burying is the behavior users do expect at the moment).

> @glutanimate is there anything you think should be addressed that shouldn't wait for a follow-up PR?

I think my main goal for this PR personally would be to come out of it with us mostly fully set on the note type. If we defer sibling burying/spacing behavior and a flag for IO note types to a follow-up PR (that I would however hope we could still merge ahead of rolling this out to testers), then I think we're mostly there.

_Originally posted by @glutanimate in https://github.com/ankitects/anki/issues/2367#issuecomment-1446098285_

The issue discusses sibling burying and spacing for image occlusion cards, with context from issue #2367. Start by reviewing that linked discussion and the existing image-occlusion and scheduling entry points, which are not named here. Done would require a settled behavior and clear acceptance criteria, neither of which this issue currently provides.

Written by the indexing model from the issue text.