Use better icon to show slashes interp looping forever

[AviFS]

For instance, maybe: …

Or maybe there's a clearer loading icon to use?

Unicode would be better than just the dots since the dots can be replaced by accident (periods).

[AviFS]

Maybe ↻ or ⟳ will work.

Or in the little side-bubble on the let where output might go, this could go in red!