NaiveDateDaysIterator is private.

[dnrusakov]

Currently, chrono::NaiveDate.iter_days() returns NaiveDateDaysIterator which is private. So, I can not store the returned iterator in the variable (or in the field of a struct), for example: let tmp: NaiveDateDaysIterator = from.iter_days() fails to compile.

The only option I have is the boxing: let tmp: Box<dyn Iterator<Item=NaiveDate>> = Box::new(from.iter_days()) which leads to unnecessary heap allocation.

Could you guys, please, make NaiveDateDaysIterator public.

[pitdicker]

Fixed in #1134.