update menu

Author: jjmax75

_includes/default.njk

@@ -34,7 +34,7 @@ title: OpenJS NodeJS Application Developer Study Guide
         <div class="sidebar column">
           <nav>
             <ul>
-              <li><a href="#" {% if page.url === '/buffer/' %} class="current" {% endif %}>Buffer and Streams</a></li>
+              <li><a href="{{ "/buffers-and-streams" | url }}" {% if page.url === '/buffers-and-streams/' %} class="current" {% endif %}>Buffer and Streams</a></li>
               <li><a href="#">Control flow</a></li>
               <li><a href="#">Child Processes</a></li>
               <li><a href="#">Diagnostics</li>