Arg constructor Null safety

1. jrpn
2. model
3. Arg
4. Arg constructor

Arg class

1. Constructors
2. Arg
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. init
8. matches
9. noSuchMethod
10. toString
11. Operators
12. operator ==
13. Static properties
14. fShift
15. gsbLabelSynonyms
16. gShift
17. kDigits
18. kDot
19. kI
20. kParenI
21. registerISynonyms
22. Static methods
23. assertStaticInitialized