title: yAxis Tooltip, formatter function, specific value
body: <p>I'm trying to edit the value that appear on the tooltip, but it's not working for a specific data value. It works fine on the default tooltip, but on that specific one does not works.</p>
  
  <p>Is it something wrong? After the 'data' I include that, the valueSuffix works and the yDecimal works. But the formatter does not work :(</p>
  
  <p>My code:</p>
  
  <pre><code>yAxis: 1,
          tooltip: {
              valueSuffix: ' ',
  
              formatter:function(){
  
                  if(this.point.y == 0)
                      return 'ON'
                  else
                      return 'OFF'
  
              },
  
              yDecimals: 0                    
          }
  </code></pre>
  
  <p>It only shows on the screen the default value (0 or 1), does not show my edited one.</p>
  
  <p>thanks :)</p>