Updated SDK sample sections

Author: gsteve88

includes/iot-hub-howto-device-twins-dotnet.md

@@ -133,7 +133,7 @@ private async Task OnDesiredPropertyChangedAsync(TwinCollection desiredPropertie
 }
 ```
 
-### SDK sample
+### SDK device sample
 
 The Azure IoT SDK for .NET provides a working sample of a device app that handles device twin tasks. For more information, see [TwinSample](https://github.com/Azure/azure-iot-sdk-csharp/tree/main/iothub/device/samples/getting%20started/TwinSample).
 
@@ -294,3 +294,7 @@ var twinsInRedmond43UsingCellular = await query.GetNextAsTwinAsync();
 Console.WriteLine("Devices in Redmond43 using cellular network: {0}", 
 string.Join(", ", twinsInRedmond43UsingCellular.Select(t => t.DeviceId)));
 ```
+
+### SDK service sample
+
+The Azure IoT SDK for .NET provides a working sample of a service app that handles device twin tasks. For more information, see [Registry Manager Sample](https://github.com/Azure/azure-iot-sdk-csharp/blob/main/iothub/service/samples/how%20to%20guides/RegistryManagerSample/RegistryManagerSample.cs).

includes/iot-hub-howto-device-twins-java.md

@@ -132,7 +132,7 @@ In this example, the `DesiredPropertiesUpdatedHandler` desired property change c
   }
 ```
 
-### SDK sample
+### SDK device sample
 
 The Azure IoT SDK for Java includes a working sample to test the device app concepts described in this article. For more information, see  [Device Twin Sample](https://github.com/Azure/azure-iot-sdk-java/tree/main/iothub/device/iot-device-samples/device-twin-sample).
 
@@ -272,3 +272,7 @@ while (twinClient.hasNextDeviceTwin(twinQuery)) {
   System.out.println(d.getDeviceId());
 }
 ```
+
+### SDK service sample
+
+The Azure IoT SDK for Java provides a working sample of a service app that handles device twin tasks. For more information, see  [Device Twin Sample](https://github.com/Azure/azure-iot-service-sdk-java/blob/main/service/iot-service-samples/device-twin-sample/src/main/java/samples/com/microsoft/azure/sdk/iot/DeviceTwinSample.java).

includes/iot-hub-howto-device-twins-node.md

@@ -222,9 +222,9 @@ You can set up a listener for a single property change. In this example, the cod
    twin.on('properties.desired.climate.hvac.systemControl', function (fanOn) {
        console.log('setting fan state to ' + fanOn);
     });
-```
+  ```
 
-### SDK samples
+### Device SDK samples
 
 The Azure IoT SDK for Node.js contains two device twin samples:
 
@@ -342,3 +342,7 @@ query.nextAsTwin(function(err, results) {
 });
 };
 ```
+
+### Service SDK sample
+
+The Azure IoT SDK for Node.js provides a working sample of a service app that handles device twin tasks. For more information, see [Device Twin Backend Service](https://github.com/Azure/azure-iot-sdk-node/tree/main/device/samples/helpers/device-twin-service) - This project is used to send device twin patch updates for a specific device.

includes/iot-hub-howto-device-twins-python.md

@@ -113,7 +113,7 @@ The `twin_patch_handler` receives and prints JSON desired property updates.
         print(twin_patch)
 ```
 
-### SDK samples
+### SDK device samples
 
 The Azure IoT SDK for Python includes the following samples:
 
@@ -198,3 +198,7 @@ print("Devices in Redmond43 plant using cellular network: {}".format(', '.join([
 
 print()
 ```
+
+### SDK service sample
+
+The Azure IoT SDK for Python provides a working sample of a service app that handles device twin tasks. For more information, see  [Registry Manager Query Sample](https://github.com/Azure/azure-iot-hub-python/blob/main/samples/iothub_registry_manager_query_sample.py).