title: Get axis name in tooltip on Highcharts
body: <p>I am using a bubble chart in Highcharts and I am trying to change the hover tooltip to show more meaningful output - at the moment I can get it to show the axis values but I cannot get it to show the labels.</p>
  
  <p>I am using this in my plotoptions:</p>
  
  <pre><code>plotOptions: {
      bubble: {
          minSize: 1,
          maxSize: 40,
          tooltip: {
              headerFormat: '&lt;b&gt;{series.name}&lt;/b&gt;&lt;br&gt;',
              pointFormat: '{point.x}:00 UTC on {point.y} =&gt; total of {point.z} tickets'
          }                   
      }       
  }
  </code></pre>
  
  <p>and in my y axis I have:</p>
  
  <pre><code>yAxis:{
      categories: ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday","Sunday"]
  }
  </code></pre>
  
  <p>which displays as:</p>
  
  <pre><code>11:00 on 0 =&gt; total of 32 tickets
  </code></pre>
  
  <p>but I would like it to show the actual day in the label:</p>
  
  <pre><code>11:00 on Monday =&gt; total of 32 tickets
  </code></pre>
  
  <p>I have looked at formatter but then I cannot seem to access the z axis as it gives an undefined.</p>
  
  <p>How can I use the y axis name in the tooltip?</p>
  
  <p><a href="http://jsfiddle.net/qvw5gurc/1/" rel="nofollow">http://jsfiddle.net/qvw5gurc/1/</a></p>