examples: replace all app.Run(iris.Addr(...)) with app.Listen just for the shake of simplicity, both are doing the same exact thing as it's described on the http listening first example.

Former-commit-id: d20afb2e899aee658a8e0ed1693357798df93462

_examples/miscellaneous/recaptcha/custom_form/main.go

@@ -24,7 +24,7 @@ func main() {
 	// pass the middleware before the main handler or use the `recaptcha.SiteVerify`.
 	app.Post("/comment", r, postComment)
 
-	app.Run(iris.Addr(":8080"))
+	app.Listen(":8080")
 }
 
 var htmlForm = `<form action="/comment" method="POST">