Move extension methods in core project to Umbraco.Extensions

src/Umbraco.Infrastructure/Compose/NestedContentPropertyComponent.cs

@@ -3,14 +3,13 @@ using System.Linq;
 using Newtonsoft.Json.Linq;
 using Umbraco.Cms.Core;
 using Umbraco.Cms.Core.Composing;
-using Umbraco.Core;
 using Umbraco.Core.PropertyEditors;
+using Umbraco.Extensions;
 using Umbraco.Web.PropertyEditors;
 using Constants = Umbraco.Cms.Core.Constants;
 
 namespace Umbraco.Web.Compose
 {
-
     /// <summary>
     /// A component for NestedContent used to bind to events
     /// </summary>