#nullable enable a bit of the rename dashboard

Author: jasonmalinowski

src/EditorFeatures/Core.Wpf/InlineRename/Dashboard/DashboardAdornmentManager.cs

@@ -2,8 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#nullable disable
-
 using System;
 using System.Linq;
 using System.Runtime.CompilerServices;
@@ -75,7 +73,7 @@ private static bool ViewIncludesBufferFromWorkspace(IWpfTextView textView, Works
                                        .Any();
         }
 
-        private static Workspace GetWorkspace(SourceTextContainer textContainer)
+        private static Workspace? GetWorkspace(SourceTextContainer textContainer)
         {
             Workspace.TryGetWorkspace(textContainer, out var workspace);
             return workspace;

src/EditorFeatures/Core.Wpf/InlineRename/Dashboard/DashboardAdornmentProvider.cs

@@ -2,8 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-#nullable disable
-
 using System;
 using System.Collections.ObjectModel;
 using System.ComponentModel.Composition;
@@ -36,7 +34,7 @@ internal class DashboardAdornmentProvider : IWpfTextViewConnectionListener
         [Order(After = PredefinedAdornmentLayers.TextMarker)]
         [Order(After = PredefinedAdornmentLayers.CurrentLineHighlighter)]
         [Order(After = PredefinedAdornmentLayers.Squiggle)]
-        internal readonly AdornmentLayerDefinition AdornmentLayer;
+        internal readonly AdornmentLayerDefinition? AdornmentLayer;
 
         [ImportingConstructor]
         [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]