Accessibility add an arrow cue that page is scrolling down or up

From a Drupal issue but seems more like a general shepherd feature (correct me if I'm wrong)

"While your demo video has scroll bars, and I have my scroll bars set to always on, some operating systems (in my case macOS) allow setting the scroll bars to only display when you need them. So people who have that setting may not be able to tell where the particular tour point of interest is on the page. So they trade information for safety.

I don't want to over-engineer this, but such people might need a brief arrow cue that we are going down the page. Maybe even one arrow for a short distance or three for a long distance. Maybe the arrow would fade in and out. If this needs to be a separate issue, please let me know and I'll be happy to file."

Start by reviewing Shepherd's tour-point scrolling behavior and the accessibility concern described here. The issue proposes several alternatives, so first resolve the arrow's direction, duration, and short-versus-long-distance behavior. Done should provide a clear cue when a tour point causes page scrolling while preserving accessible tour use.