Fix typo

Iot Hub -> IoT Hub

Author: changeworld

includes/iot-hub-howto-cloud-to-device-messaging-java.md

@@ -210,7 +210,7 @@ IotHubServiceClientProtocol protocol = IotHubServiceClientProtocol.AMQPS;
 
 ##### Create the ServiceClient object
 
-Create the [ServiceClient](/java/api/com.azure.core.annotation.serviceclient) object, supplying the Iot Hub connection string and protocol.
+Create the [ServiceClient](/java/api/com.azure.core.annotation.serviceclient) object, supplying the IoT Hub connection string and protocol.
 
 ```java
 String connectionString = "{yourhubconnectionstring}";