Result of a single iteration of [CodePointRangeIterator].
Logically can be considered to be an Option<RangeInclusive<DiplomatChar>>,
start and end represent an inclusive range of code points [start, end],
and done will be true if the iterator has already finished. The last contentful
iteration will NOT produce a range done=true, in other words start and end are useful
values if and only if done=false.
Result of a single iteration of [
CodePointRangeIterator]. Logically can be considered to be anOption<RangeInclusive<DiplomatChar>>,startandendrepresent an inclusive range of code points [start, end], anddonewill be true if the iterator has already finished. The last contentful iteration will NOT produce a range done=true, in other wordsstartandendare useful values if and only ifdone=false.