Apply DebuggerDisplayAttribute to PEFile for easier debugging.

ICSharpCode.Decompiler/Metadata/PEFile.cs

@@ -19,6 +19,7 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Reflection.Metadata;
@@ -41,6 +42,7 @@ namespace ICSharpCode.Decompiler.Metadata
 	/// system from multiple PEFiles. This allows the caches to be shared across multiple
 	/// decompiled type systems.
 	/// </remarks>
+	[DebuggerDisplay("{FileName}")]
 	public class PEFile : IDisposable, TypeSystem.IModuleReference
 	{
 		public string FileName { get; }