Add OutputHandle enum to use instead of &mut dyn io::Write

src/pretty_printer.rs

@@ -300,7 +300,7 @@ impl<'a> PrettyPrinter<'a> {
 
         // Run the controller
         let controller = Controller::new(&self.config, &self.assets);
-        controller.run(inputs.into_iter().map(|i| i.into()).collect())
+        controller.run(inputs.into_iter().map(|i| i.into()).collect(), None)
     }
 }