[5.3] Cleanup route:list command.

[garygreen]

Sorry about last PR. Was an oversight on my behalf for the new closure-style middlewares. I've tested this with closures, single function controllers, all working.

With this PR you'll see Closure in the middleware list, so at least you know some kind of middleware is being registered in controllers, if applicable.

[ntzm]

Don't know what the standards are for Laravel, but I (personally) would rewrite this with references:

foreach ($middlewares as &$middleware) {
    if ($middleware instanceof Closure) {
        $middleware = 'Closure';
    }
}

[taylorotwell]

Nice, thanks. Changed over the loop to use a collection->map operation.