FunctionDeclarationMacro constructor Null safety

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

FunctionDeclarationMacro class

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