Expose ElementType and KeyType on JsonTypeInfo metadata. #77306
Description
public class partial JsonTypeInfo
{
public Type? KeyType { get; } // relevant for JsonTypeInfoKind.Dictionary
public Type? ElementType { get; } // relevant for JsonTypeInfoKind.Enumerable/Dictionary
}These APIs are useful for querying the model, i.e.: generating docs, schema. It's not exactly trivial to implement them but we already store this data internally.
cc: @captainsafia