Address review comments

404.html

@@ -1,6 +1,7 @@
 ---
 layout: default
 title: 404
+permalink: /404.html
 ---
 <div class="container-lg px-3">
   <header class="py-6">
@@ -11,10 +12,10 @@ title: 404
             <code style="font-size: 1.05em">404</code>: Page not found
           </h1>
           <h2 class="alt-h2 lh-condensed">
-            Something’s missing.
+            Something&rsaquo;s missing.
           </h2>
           <p class="alt-lead text-gray-light mt-2 lh-condensed" style="opacity: 0.6">
-            The page at this URL doesn’t exist.<br>
+            The page at this URL doesn&rsaquo;t exist.<br>
             Are you looking for <a href="/">the homepage</a> or <a href="/docs">the docs?</a>
           </p>
         </div>