HourFormat constructor Null safety

1. Flutter
2. material
3. HourFormat
4. HourFormat const constructor

HourFormat enum

1. Constructors
2. HourFormat
3. Values
4. HH
5. H
6. h
7. Properties
8. hashCode
9. index
10. runtimeType
11. Methods
12. noSuchMethod
13. toString
14. Operators
15. operator ==
16. Constants
17. values