[intro_equatable] Person override == and hashcode

person.dart

class Person {
 final String name;
 final int age;
  
 const Person({this.name, this.age});
  
 @override
 bool operator ==(Object other) =>
  identical(this, other) ||
  other is Person &&
  runtimeType == other.runtimeType &&
  name == other.name &&
  age == other.age;

 @override
 int get hashCode => name.hashCode ^ age.hashCode;
}