separate attributes into their own namespace (fixes YarnSpinnerTool#279)

Editor/Editors/DialogueRunnerEditor.cs

@@ -14,6 +14,7 @@ Yarn Spinner is licensed to you under the terms found in the file LICENSE.md.
 using System;
 using System.Reflection;
 using Yarn.Unity.UnityLocalization;
+using Yarn.Unity.Attributes;
 
 namespace Yarn.Unity.Editor
 {

Runtime/Attributes/Attributes.cs

@@ -1,6 +1,6 @@
 using System;
 
-namespace Yarn.Unity
+namespace Yarn.Unity.Attributes
 {
 
 #nullable enable

Runtime/DialogueRunner.cs

@@ -11,6 +11,7 @@ Yarn Spinner is licensed to you under the terms found in the file LICENSE.md.
 using UnityEngine.Events;
 using System;
 using UnityEngine.UIElements;
+using Yarn.Unity.Attributes;
 
 
 #nullable enable

Runtime/Views/VoiceOverView.cs

@@ -5,6 +5,7 @@ Yarn Spinner is licensed to you under the terms found in the file LICENSE.md.
 using System;
 using System.Collections;
 using UnityEngine;
+using Yarn.Unity.Attributes;
 
 namespace Yarn.Unity
 {