Open local development site in browser on run

         import asyncio
 
         if self.port:
+            webbrowser.open(f"http://localhost:{self.port}")
             asyncio.run(web.serve(self.app, port=self.port, watch_dir=self.watch))
         elif self.socket:
             asyncio.run(web.serve(self.app, socket=self.socket, watch_dir=self.watch))