Add 'report a bug' button

assets/stylesheets/components/_header.scss

@@ -62,7 +62,7 @@
   top: .25rem;
   right: .25rem;
   width: 8.5rem;
-  height: calc(13.75rem + 1px);
+  height: calc(2.25rem  * 6 + 2.5rem + 1px); // (height of each menu element * total menu elements + menu title element total height + menu title border size)
   white-space: nowrap;
   word-wrap: normal;
   overflow-wrap: normal;

views/app.erb

@@ -25,6 +25,7 @@
       <a href="/news" class="_menu-link">Changelog</a>
       <a href="/help" class="_menu-link">Guide</a>
       <a href="/about" class="_menu-link">About</a>
+      <a href="https://github.com/freeCodeCamp/devdocs/issues/new/choose" class="_menu-link">Report a bug</a>
     </nav>
   </header>
   <section class="_sidebar" tabindex="-1">