Moving over at item that's resting on ice gives a message about there
being ice present and then about the item, whether mention_decor is On
or Off. With it On, you'll get a message about being back on solid
ground as soon as you leave the ice. With it Off you wouldn't get
that at all if not levitating; that's the basic no-mention_decor
behavior for ice. However, if you were levitating, you would get a
delayed "back on solid ground" message when moving over some other
object, which might occur quite a bit later. Autopickup handling is
calling describe_decor() when the hero is levitating and some of that
wasn't appropriate for no-mention_decor.
This issue has been present since I first implemented mention_decor,
not introduced by recent back_on_ground() changes.
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