feat: add explanation of genres

Author: guerda

templates/genres.html

@@ -11,6 +11,7 @@
     {% include 'navigation.html' %}
     <content>
       <h2>Genres</h2>
+        <p>Here is an overview of your top genres for your albums.</p>
         <div id="plot"></div>
     </content>
     {% include 'footer.html' %}