Customizing default y-axis label in Highcharts
<p>I want to prefix a $ to the default y-axis label.  My bar chart is using values in the millions so the chart is returning value-MM (80MM, 30MM).  What I would like to do is format the y-axis like $-value-MM ($80MMm $30MM).  I have tried the code below and can't get it to work?</p>

<pre><code>yAxis: [{ // Primary yAxis
    labels: {
        formatter: function () {
            return '$' + this.value;
        }
    },
    title: {
        text: 'Revenue',
</code></pre>