Add information about debug info source to ILSpy UI.

ILSpy/Languages/CSharpLanguage.cs

@@ -356,6 +356,10 @@ namespace ICSharpCode.ILSpy
 					if (runtimeName != null) {
 						output.WriteLine("// Runtime: " + runtimeName);
 					}
+					var debugInfo = assembly.GetDebugInfoOrNull();
+					if (debugInfo != null) {
+						output.WriteLine("// Debug info: " + debugInfo.Description);
+					}
 					output.WriteLine();
 
 					CSharpDecompiler decompiler = new CSharpDecompiler(typeSystem, assemblyResolver, options.DecompilerSettings);

ILSpy/TreeNodes/AssemblyTreeNode.cs

@@ -103,6 +103,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 						tooltip.Inlines.Add(new Bold(new Run("Runtime: ")));
 						tooltip.Inlines.Add(new Run(runtimeName));
 					}
+					var debugInfo = LoadedAssembly.GetDebugInfoOrNull();
+					tooltip.Inlines.Add(new LineBreak());
+					tooltip.Inlines.Add(new Bold(new Run("Debug info: ")));
+					tooltip.Inlines.Add(new Run(debugInfo?.Description ?? "none"));
 				}
 
 				return tooltip;