[5.x] Add support for $view parameter closure with Route::statamic()

[jesseleite]

This PR adds support for optional $view parameter closure with Statamic::route(), so that you can dynamically render a view from a route segment.

For example, this works fine in Laravel...

Route::get('/components/{component}', function ($component) {
    return view($component);
});

So this should work with Statamic routes as well...

Route::statamic('/components/{component}', function ($component) {
    return view($component);
});

This PR makes it work like this...

TODO

• Support closure in second $view parameter
• Support closure in third $data parameter
  • This was already supported, but we just want to make sure we don't regress here
• Support type-hinted service-container-friendly dependency injection like Laravel does
• Throw helpful exception if they try to use both closures
  • This wouldn't make sense. If you're returning view($template, $data) in Laravel, it's expected you'll pass your dynamic data directly into that 👍
• Add test coverage
• Add docs
  • Dynamic closure based routes docs#1614

References #9953

[jasonvarga]

The only thing I'd want to change is to make sure if you use Request $request as the first argument of the closure that it'd work too, like a regular route.

Route::statamic('foo/{bar}', function ($bar) {
  return view('myview', ['bar' => $bar];
});

Route::statamic('foo/{bar}', function (Request $request, $bar) {
  return view('myview', ['bar' => $bar];
});

(Maybe it already does work, but a test to show it would be good.)

[jesseleite]

@jasonvarga After some further testing, technically Request $request doesn't have to come first with Route::get().

Also, Laravel supports and documents type-hinted service-container-friendly dependency injection in general.

I figured we might as well go for feature parity with Route::get(), so now this works 🎉

Route::statamic('example/{one}', function ($one, Request $request, Joe $joe) {
    ray($one, $request, $joe);
});

Change was made