fix #22205: microtonal accidentals that change pitch display as naturals

Microtonal accidentals are treated as naturals for playback purposes, but they were also *displaying* as naturals as well in cases where an actual natural sign would not have been merely cautionary (eg, if the note was already flat or sharp because of the key signature or an earlier accidental).  This PR fixes that bug

I also added some commented-out code that would cause microtonal accidentals to also be treated as naturals rather than no-ops in terms of how they affect the "accidental state" - the pitch of subsequent notes in the measure.  We'll probably want to enable this code (or build on it) if we ever implement playback of microtonal accidentals.  But for now, it would represent an incompatible change and should probably remain disabled.