Fixed failing unit test.

src/Umbraco.Infrastructure/PropertyEditors/MissingPropertyEditor.cs

@@ -8,7 +8,7 @@ namespace Umbraco.Core.PropertyEditors
     /// </summary>
     public class MissingPropertyEditor : IDataEditor
     {
-        public string Alias => "missing";
+        public string Alias => "Umbraco.Missing";
 
         public EditorType Type => EditorType.Nothing;
 

src/Umbraco.Tests/Composing/TypeLoaderTests.cs

@@ -275,7 +275,7 @@ AnotherContentFinder
         public void GetDataEditors()
         {
             var types = _typeLoader.GetDataEditors();
-            Assert.AreEqual(38, types.Count());
+            Assert.AreEqual(39, types.Count());
         }
 
         /// <summary>