[Proposal] Add parameters to change the name of the properties generated by KeyValuePairConverter

[Pretasoc]

It would be nice, if we could add a constructor to KeyValuePairConverter so we can specify alternate names for Key and Value by using the Parameter property of the JsonConverterAttribute.

Consider this example

public class Student {}
public class Grade {}

[JsonArray(ItemConverterType = typeof(KeyValuePairConverter), ItemConverterParameters = new object[]{"Student", "Grade"})]
public class GradeDictionary : Dictionary<Student, Grade>{}

public class Course
{

    public GradeDictionary  Grades { get; } = new();
}

With the change we would get

{
    "Grades": [
        {
            "Student": {...},
            "Grade": {...}
        },
        ...

    ]
}