FieldDefinitionMacro constructor Null safety

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

FieldDefinitionMacro class

1. Constructors
2. FieldDefinitionMacro
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. visitFieldDefinition
10. Operators
11. operator ==