Add a sniff to check for "Class Example" doc comments

Problem: developers just repeat the class name in a doc comment, which is useless:

namespace Drupal\example\Form;

use Drupal\Core\Form\ConfigFormBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Class Example.
 */
class Example extends ConfigFormBase {

Such a comments does not carry any additional information, the only benefit is the visual separation between the use statements and the beginning of the class.

Solution: create a sniff that checks if the class short comment only consists of 2 words. If one word is the class then throw a warning "The class short comment should describe what the class does and not simply repeat the class name."