Add comments step part to reader

Author: shaedrich

src/PhpWord/Reader/Word2007.php

@@ -57,7 +57,8 @@ public function load($docFile)
             ['stepPart' => 'document', 'stepItems' => [
                 'endnotes' => 'Endnotes',
                 'footnotes' => 'Footnotes',
-                'settings' => 'Settings',
+                'settings'  => 'Settings',
+                'comments' => 'Comments'
             ]],
         ];