ParameterType constructor Null safety

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

ParameterType class

1. Constructors
2. ParameterType
3. Properties
4. hashCode
5. name
6. required
7. runtimeType
8. type
9. Methods
10. noSuchMethod
11. toString
12. Operators
13. operator ==