chore(demo): add more descriptive notification content

Author: javier-godoy

src/test/java/com/flowingcode/addons/ycalendar/ExtendedDatePickerDemo.java

@@ -41,7 +41,7 @@ public ExtendedDatePickerDemo() {
     // #endif
 
     field.addValueChangeListener(ev->{
-      Notification.show(Objects.toString(ev.getValue()));
+      Notification.show("Date changed to: " + Objects.toString(ev.getValue()));
     });
 
     field.setClassNameGenerator(date -> {

src/test/java/com/flowingcode/addons/ycalendar/InlineDatePickerDemo.java

@@ -40,7 +40,7 @@ public InlineDatePickerDemo() {
     // #endif
 
     field.addValueChangeListener(ev->{
-      Notification.show(Objects.toString(ev.getValue()));
+      Notification.show("Date changed to: " + Objects.toString(ev.getValue()));
     });
 
     field.setClassNameGenerator(date -> {