add note about adding things to log

index.html

@@ -252,6 +252,7 @@
       <div class="row">
         <div class="export-logs col-8">
           <p>Download or copy the player logs, which should be included when submitting a playback issue.</p>
+          <p>To insert a comment into the player log, use <code>player.log()</code> in the console, e.g. <code>player.log('Seeking to 500');player.currentTime(500);</code></p>
           <button id="download-logs" class="btn btn-outline-secondary">
             <span class="icon">
               <svg xmlns="http://www.w3.org/2000/svg" height="24px" viewBox="0 -960 960 960" width="24px" fill="#5f6368">