Update controller examples

[retlehs]

spurred from https://discourse.roots.io/t/best-practice-resources-for-blade/8341/141?u=benword

regarding the About.php file prior to this PR... it did nothing. ideally you'd create a template-about.php controller and template file, then drop this in the controller:

<?php

namespace App;
use Sober\Controller\Controller;

class TemplateAbout extends Controller
{

}

[robrecord]

Thank you for this, I was mightily confused!