title: UpsetR: add numeric labels to set size on plot
body: <p>Is there any way to add labels on top of the set size bars in UpsetR similar to the show.numbers for the main intersection graph?</p>
  <pre><code>test &lt;- upset(grouped_hot,
                sets                = c(&quot;A&quot;, &quot;B&quot;, &quot;C&quot;, &quot;N&quot;),
                nintersects         = 8,
                mb.ratio            = c(0.6, 0.4),
                sets.x.label        = &quot;Number of Patients&quot;,
                sets.bar.color      =  &quot;#56B4E9&quot;,
                mainbar.y.label     = &quot;Number of Patients&quot;,
                order.by            = &quot;freq&quot;,
                empty.intersections = &quot;on&quot;,
                keep.order          = FALSE,
                scale.sets          = &quot;identity&quot;,
                att.pos             = &quot;top&quot;,
                text.scale          = c(2.5, 2.5, 2, 1.5, 2.5, 2.5))
  </code></pre>
  <p>Expected result is to have labels over each of the set size bars stating the size.</p>