Fix code style and bump to php 7.4

tests/unit/DocBlock/DescriptionTest.php

@@ -165,7 +165,7 @@ class DescriptionTest extends TestCase
         {% endfor %}';
         EOT;
 
-        $fixture  = new Description($body, []);
+        $fixture = new Description($body, []);
 
         $this->assertSame($expected, (string) $fixture);
     }

tests/unit/DocBlock/ExampleFinderTest.php

@@ -14,8 +14,7 @@ use PHPUnit\Framework\TestCase;
  */
 class ExampleFinderTest extends TestCase
 {
-    /** @var ExampleFinder */
-    private $fixture;
+    private ExampleFinder $fixture;
 
     /**
      * Call Mockery::close after each test.