Add debug for polymorphic pass through.

ast-generator/src/lib.rs

@@ -49,6 +49,12 @@ fn debug_built_spec(build_spec: &BuildSpec, token_stream: &TokenStream) {
                 polymorphic_enum_loop_build_spec.name()
             );
         }
+        BuildSpec::PolymorphicPassThrough(pass_through_build_spec) => {
+            println!(
+                "Polymorphic Pass Through Spec - name: {}",
+                pass_through_build_spec.name()
+            );
+        }
     }
     println!("{:#?}", token_stream);
     let parsed: File = syn::parse2(token_stream.clone()).unwrap();