Update src/PowerShellEditorServices/Utility/Utils.cs

Co-Authored-By: rjmholt <[email protected]>

Author: SeeminglyScience

src/PowerShellEditorServices/Utility/Utils.cs

@@ -3,6 +3,7 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 //
 
+using System;
 using System.Runtime.InteropServices;
 
 namespace Microsoft.PowerShell.EditorServices