[Misc] Avoid checkstyle errors with empty blocks

xwiki-platform-core/xwiki-platform-resource/xwiki-platform-resource-api/src/main/java/org/xwiki/resource/events/AbstractResourceReferenceHandlerEvent.java

@@ -43,7 +43,7 @@ public abstract class AbstractResourceReferenceHandlerEvent implements ResourceR
      */
     public AbstractResourceReferenceHandlerEvent()
     {
-
+        // Empty voluntarily, just here to offer a default constructor
     }
 
     /**

xwiki-platform-core/xwiki-platform-resource/xwiki-platform-resource-api/src/main/java/org/xwiki/resource/events/ResourceReferenceHandledEvent.java

@@ -45,7 +45,7 @@ public class ResourceReferenceHandledEvent extends AbstractResourceReferenceHand
      */
     public ResourceReferenceHandledEvent()
     {
-
+        // Empty voluntarily, just here to offer a default constructor
     }
 
     /**

xwiki-platform-core/xwiki-platform-resource/xwiki-platform-resource-api/src/main/java/org/xwiki/resource/events/ResourceReferenceHandlingEvent.java

@@ -44,7 +44,7 @@ public class ResourceReferenceHandlingEvent extends AbstractResourceReferenceHan
      */
     public ResourceReferenceHandlingEvent()
     {
-
+        // Empty voluntarily, just here to offer a default constructor
     }
 
     /**