chore: disable MarkdigExtensionSettingConverter JSON formatting

Author: filzrev

src/Docfx.MarkdigEngine.Extensions/MarkdigExtensionSettingConverter.NewtonsoftJson.cs

@@ -47,7 +47,7 @@ public override object ReadJson(JsonReader reader, Type objectType, object exist
                         }
 
                         // Convert JToken to JsonElement.
-                        var json = options.ToString();
+                        var json = options.ToString(Formatting.None);
                         using var doc = System.Text.Json.JsonDocument.Parse(json);
                         var jsonElement = doc.RootElement.Clone();
 
@@ -78,7 +78,7 @@ public override void WriteJson(JsonWriter writer, object value, JsonSerializer s
             {
                 writer.WriteStartObject();
                 writer.WritePropertyName(model.Name);
-                var json = model.Options.ToString();
+                var json = System.Text.Json.JsonSerializer.Serialize(model.Options, DefaultSerializerOptions);
                 writer.WriteRawValue(json);
                 writer.WriteEndObject();
             }

src/Docfx.MarkdigEngine.Extensions/MarkdigExtensionSettingConverter.SystemTextJson.cs

@@ -66,7 +66,7 @@ public override void Write(Utf8JsonWriter writer, MarkdigExtensionSetting value,
             {
                 writer.WriteStartObject();
                 writer.WritePropertyName(model.Name);
-                var json = model.Options.ToString();
+                var json = JsonSerializer.Serialize(model.Options, DefaultSerializerOptions);
                 writer.WriteRawValue(json);
                 writer.WriteEndObject();
             }