MethodTypeMacro constructor Null safety

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

MethodTypeMacro class

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