Added classes-constructor and removed description from templates

assets/templates/_header.phtml

@@ -5,7 +5,7 @@
     <meta charset="utf-8">
 
     <title><?= $title ?? 'PHP Apprentice' ?></title>
-    <meta name="description" content="<?= $description ?? 'A site for learning how to use PHP'?>">
+    <meta name="description" content="<?= $subtitle ?? 'A site for learning how to use PHP' ?>">
     <meta name="viewport" content="width=device-width, initial-scale=1">
 
     <link rel="stylesheet" href="/css/site.css">

assets/templates/_table_of_contents.phtml

@@ -14,6 +14,7 @@
         <li><a href="<?= page_path('classes') ?>">Classes: Introduction</a></li>
         <li><a href="<?= page_path('classes-inheritance') ?>">Classes: Inheritance</a></li>
         <li><a href="<?= page_path('classes-visibility') ?>">Classes: Visibility</a></li>
+        <li><a href="<?= page_path('classes-constructor') ?>">Classes: Constructor</a></li>
     </ol>
     <a href="<?= page_path('credits') ?>">Credits</a>
 </div>

assets/templates/default.phtml

@@ -1,4 +1,4 @@
-<?php partial('header', ['title' => $title, 'description' => $description]) ?>
+<?php partial('header', ['title' => $title, 'subtitle' => $subtitle]) ?>
 
 <div class="menu">
     <button class="menu-button" title="Open Menu">