Update coding style to include PSR-12, among other options

This also includes heavy use of slevomat/coding-standard to apply
various checks to the code, based on maintainer (me) preference.

src/Generator/RandomLibAdapter.php

@@ -1,4 +1,5 @@
 <?php
+
 /**
  * This file is part of the ramsey/uuid library
  *
@@ -7,21 +8,20 @@
  *
  * @copyright Copyright (c) Ben Ramsey <ben@benramsey.com>
  * @license http://opensource.org/licenses/MIT MIT
- * @link https://benramsey.com/projects/ramsey-uuid/ Documentation
- * @link https://packagist.org/packages/ramsey/uuid Packagist
- * @link https://github.com/ramsey/uuid GitHub
  */
 
+declare(strict_types=1);
+
 namespace Ramsey\Uuid\Generator;
 
-use RandomLib\Generator;
 use RandomLib\Factory;
+use RandomLib\Generator;
 
 /**
- * RandomLibAdapter provides functionality to generate strings of random
- * binary data using the paragonie/random-lib library
+ * RandomLibAdapter generates strings of random binary data using the
+ * paragonie/random-lib library
  *
- * @link https://packagist.org/packages/paragonie/random-lib
+ * @link https://packagist.org/packages/paragonie/random-lib paragonie/random-lib
  */
 class RandomLibAdapter implements RandomGeneratorInterface
 {
@@ -31,31 +31,24 @@ class RandomLibAdapter implements RandomGeneratorInterface
     private $generator;
 
     /**
-     * Constructs a `RandomLibAdapter` using a `RandomLib\Generator`
+     * Constructs a RandomLibAdapter
      *
-     * By default, if no `Generator` is passed in, this creates a high-strength
+     * By default, if no Generator is passed in, this creates a high-strength
      * generator to use when generating random binary data.
      *
-     * @param Generator $generator An paragonie/random-lib `Generator`
+     * @param Generator|null $generator The generator to use when generating binary data
      */
-    public function __construct(Generator $generator = null)
+    public function __construct(?Generator $generator = null)
     {
         if ($generator === null) {
             $factory = new Factory();
-
             $generator = $factory->getHighStrengthGenerator();
         }
 
         $this->generator = $generator;
     }
 
-    /**
-     * Generates a string of random binary data of the specified length
-     *
-     * @param int $length The number of bytes of random binary data to generate
-     * @return string|null A binary string
-     */
-    public function generate(int $length): ?string
+    public function generate(int $length): string
     {
         return $this->generator->generate($length);
     }