Fix typo, adds [CannotSuppressNotification]

src/Umbraco.Core/Notifications/CannotSuppressNotificationAttribute.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace Umbraco.Cms.Core.Notifications
+{
+    [AttributeUsage(AttributeTargets.Class)]
+    internal sealed class CannotSuppressNotificationAttribute : Attribute
+    {
+    }
+}

src/Umbraco.Core/Notifications/ContentRefreshNotification.cs

@@ -5,7 +5,9 @@ using Umbraco.Cms.Core.Models;
 
 namespace Umbraco.Cms.Core.Notifications
 {
+
     [Obsolete("This is only used for the internal cache and will change, use saved notifications instead")]
+    [CannotSuppressNotification]
     [EditorBrowsable(EditorBrowsableState.Never)]
     public class ContentRefreshNotification : EntityRefreshNotification<IContent>
     {

src/Umbraco.Core/Notifications/MediaRefreshNotification.cs

@@ -5,6 +5,7 @@ using Umbraco.Cms.Core.Models;
 
 namespace Umbraco.Cms.Core.Notifications
 {
+    [CannotSuppressNotification]
     [Obsolete("This is only used for the internal cache and will change, use tree change notifications instead")]
     [EditorBrowsable(EditorBrowsableState.Never)]
     public class MediaRefreshNotification : EntityRefreshNotification<IMedia>

src/Umbraco.Core/Notifications/MemberRefreshNotification.cs

@@ -5,6 +5,7 @@ using Umbraco.Cms.Core.Models;
 
 namespace Umbraco.Cms.Core.Notifications
 {
+    [CannotSuppressNotification]
     [Obsolete("This is only used for the internal cache and will change, use tree change notifications instead")]
     [EditorBrowsable(EditorBrowsableState.Never)]
     public class MemberRefreshNotification : EntityRefreshNotification<IMember>

src/Umbraco.Core/Notifications/ScopedEntityRemoveNotification.cs

@@ -5,6 +5,7 @@ using Umbraco.Cms.Core.Models;
 
 namespace Umbraco.Cms.Core.Notifications
 {
+    [CannotSuppressNotification]
     [Obsolete("This is only used for the internal cache and will change, use tree change notifications instead")]
     [EditorBrowsable(EditorBrowsableState.Never)]
     public class ScopedEntityRemoveNotification : ObjectNotification<IContentBase>