factLink constant Null safety

1. fact_browser
2. constants
3. DbFields
4. factLink constant

DbFields class

1. Constructors
2. DbFields
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Constants
12. factArchivedLink
13. factAuthor
14. factDay
15. factLanguage
16. factLink
17. factMedia
18. factMonth
19. factText
20. factYear
21. statementAuthor
22. statementCategory
23. statementCorrectness
24. statementDay
25. statementFactcheckIDs
26. statementLanguage
27. statementLink
28. statementMedia
29. statementMediatype
30. statementMonth
31. statementPicture
32. statementPictureCopyright
33. statementPictureFile
34. statementRectification
35. statementText
36. statementYear