Staff Type Dlg Box - TAB: Remove "on_" from slot names.


Qt uses the prefix for automatic signal-slot matching and generates run-time warnings if no match is found.
Merge pull request #275 from mgavioli/TAB_type_edit_slot_names

Staff Type Dlg Box - TAB: Remove "on_" from slot names.
fix #20508: Clefs and key sigs drawn wrongly in palettes