FieldDefinitionBuilder constructor Null safety

1. macro_builder
2. definition
3. FieldDefinitionBuilder
4. FieldDefinitionBuilder constructor

FieldDefinitionBuilder class

1. Constructors
2. FieldDefinitionBuilder
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. typeDefinitionOf
10. withGetterSetterPair
11. withInitializer
12. Operators
13. operator ==