Update HasValue obsolete message

Author: ronaldbarendse

src/Umbraco.Core/PropertyEditors/PropertyValueConverterBase.cs

@@ -31,7 +31,7 @@ public virtual bool IsConverter(IPublishedPropertyType propertyType)
             }
         }
 
-        [Obsolete("This method is not part of the IPropertyValueConverter contract and therefore not used, use IsValue instead.")]
+        [Obsolete("This method is not part of the IPropertyValueConverter contract, therefore not used and will be removed in future versions; use IsValue instead.")]
         public virtual bool HasValue(IPublishedProperty property, string culture, string segment)
         {
             var value = property.GetSourceValue(culture, segment);