fix #24102: pedal sounds in wrong instrument

pedal was always being applied to top part of score rather than the part
actually applied to
fix #23366: yet another left over CamelCase...
handle channel changes too
fix #23999: instrument change produces incorrect mixer details
fix #24245: slurs in voice > 1 attach to wrong voice on load
No html needed here

eases the process of translating
back to # and b for translatable strings in CPP files

due to a bug in lupdate, see
https://bugreports.qt-project.org/browse/QTBUG-35164
revert back to plain # and b in CPP files

but also make these strings translatable
rework text implementation
fix #24072: Changing measure actual duration shifts all subsequent spanners
fix: undo of change actual duration to 8/4 doesn't undo rest shape change
implement drag&drop of symbols to text
fix #24562: Volta incorrect with multimeasure rests enabled
fix #24562: Volta incorrect with multimeasure rests enabled
fix #24655: ledger lines too thin
fix tests
update regression tests
implement drag&drop of symbols from palette to text in edit mode
make master palette accessible during text edit; fix regression: text not movable
initialize TextCursor with TextStyle