title: Add an arrow with filled head to ggplot by geom_label_repel
body: <p>I want to add an arrow with a filled head to a ggplot object by using the <code>geom_label_repel</code> function. I thought that I could use: <code>arrow.fill = 'black'</code> like I do with the <code>geom_segment</code>, but it does not work in the <code>geom_label_repel</code>. Is it another way to get a filled arrow?</p>
  <p>The reason why I use the <code>geom_label_repel</code> is that it was the only way I managed to start the arrow at the border of the label. If this coordinate can be found in another way, I could use the <code>geom_segment</code> instead.</p>
  <pre><code>library(tidyverse)
  library(ggrepel)
  
  dmax &lt;- iris %&gt;%
    filter(Sepal.Length == max(Sepal.Length))
  
  ggplot(data = iris, aes(x=Sepal.Width, y=Sepal.Length)) +
    geom_point() +
    geom_label_repel(data=dmax, aes(label = 'max'), 
                     box.padding = unit(.25, 'lines'), 
                     point.padding = unit(1.5, 'lines'), 
                     arrow = arrow(length = unit(0.25, 'cm'), type = 'closed')) +
    geom_segment(aes(x=3, xend=max(Sepal.Width), y=0, yend=max(Sepal.Width)), 
                 arrow=arrow(length = unit(0.25, 'cm'), type = 'closed'), 
                 arrow.fill = 'black')
  </code></pre>