Add reference to System.Text.Json

Author: strobelt

src/libraries/System.Text.Json/ref/System.Text.Json.cs

@@ -1040,6 +1040,7 @@ public static partial class JsonMetadataServices
         public static System.Text.Json.Serialization.JsonConverter<ulong> UInt64Converter { get { throw null; } }
         public static System.Text.Json.Serialization.JsonConverter<System.Uri> UriConverter { get { throw null; } }
         public static System.Text.Json.Serialization.JsonConverter<System.Version> VersionConverter { get { throw null; } }
+        public static System.Text.Json.Serialization.JsonConverter<System.Text.Json.JsonDocument> DocumentConverter { get { throw null; } }
         public static System.Text.Json.Serialization.Metadata.JsonTypeInfo<TElement[]> CreateArrayInfo<TElement>(System.Text.Json.JsonSerializerOptions options, System.Text.Json.Serialization.Metadata.JsonCollectionInfoValues<TElement[]> collectionInfo) { throw null; }
         public static System.Text.Json.Serialization.Metadata.JsonTypeInfo<TCollection> CreateConcurrentQueueInfo<TCollection, TElement>(System.Text.Json.JsonSerializerOptions options, System.Text.Json.Serialization.Metadata.JsonCollectionInfoValues<TCollection> collectionInfo) where TCollection : System.Collections.Concurrent.ConcurrentQueue<TElement> { throw null; }
         public static System.Text.Json.Serialization.Metadata.JsonTypeInfo<TCollection> CreateConcurrentStackInfo<TCollection, TElement>(System.Text.Json.JsonSerializerOptions options, System.Text.Json.Serialization.Metadata.JsonCollectionInfoValues<TCollection> collectionInfo) where TCollection : System.Collections.Concurrent.ConcurrentStack<TElement> { throw null; }