unsigned isNonMarkingChar(const String& s, unsigned offset, int* spacing, BreakId* breakability)
isNonMarkingChar(Char ch, Char modifier, int* spacing, BreakId* breakability)
unsigned isNonMarkingChar(const String& s, unsigned offset, int* spacing, BreakId* breakability){  assert(offset < s.GetLength());  Char ch = s.GetChar(offset);  Char modifier = (offset + 1 < s.GetLength() && isVariant(s.GetChar(offset + 1))) ? s.GetChar(offset + 1) : 0;  return isNonMarkingChar(ch, modifier, spacing, breakability);}