Re: Fixes NoteColumn vs SpanBar collisions. (issue 5323062)

[Keith OHara]

> This fixes the SpanBar regression ID'd by Phil. 

Well, not exactly.  The failing regression test said:
 texidoc = "SpanBars participate in the horizontal collision system;
 the accidentals should not collide with the bar lines."

This patch implements issue 1955, keeping accidentals, fingerings, etc.,
from folding above/below bar lines at all.  Thus this patch moves the 
accidental away from the extended bar line, whether there is a span bar 
or not (e.g., whether in a PianoStaff or ChoirStaff).

So if we take this patch, we should probably change the regression test,
as well, because the SpanBars will not actually be participating in the 
horizontal collision system.
(e.g., if somebody does \remove "Bar_engraver", the accidental collides
with the span bar again.)