feat: mark more generated code as generated wrt dotnet/runtime#64541

src/Dnet.SourceGenerators/CommonGenerators.cs

@@ -126,7 +126,7 @@ private static void AddSources(IncrementalGeneratorPostInitializationContext con
     {
         foreach (var result in sources)
         {
-            context.AddSource(result.Name, result.Text);
+            context.AddSource(result.Name + ".g", "// <auto-generated/>" + Environment.NewLine + result.Text);
         }
     }