Document ignored cancellation token

src/VisualStudio/Core/Impl/CodeModel/FileCodeModel.cs

@@ -123,7 +123,14 @@ internal override void Shutdown()
                 // We don't want to block up file removal on the UI thread since we want that path to stay asynchronous.
                 CodeModelService.DetachFormatTrackingToBuffer(_invisibleEditor.TextBuffer);
 
-                State.ProjectCodeModelFactory.ScheduleDeferredCleanupTask(cancellationToken => { _invisibleEditor.Dispose(); });
+                State.ProjectCodeModelFactory.ScheduleDeferredCleanupTask(
+                    cancellationToken =>
+                    {
+                        // Ignore cancellationToken: we always need to call Dispose since it triggers the file save.
+                        _ = cancellationToken;
+
+                        _invisibleEditor.Dispose();
+                    });
             }
 
             base.Shutdown();