title: Add annotation text in an arrow in ggplot2
body: <p>I have the dataframe below:</p>
  
  <pre><code>df &lt;- data.frame(result=floor(rnorm(1000, 100, 20)))    
  </code></pre>
  
  <p>to create this histogram:</p>
  
  <pre><code>require(scales)
  df &lt;- data.frame(result=floor(rnorm(1000, 100, 20)))   
  ggplot(df)+
    geom_histogram(aes(result, fill = (result&lt;=80 | result &gt; 95)),
                   binwidth = 5, center = 2.5, color = "black") +
    scale_fill_manual(values=c("darkblue", "lightblue"), guide = F) +
    labs(y = "Frequency", x = "Result") + scale_y_continuous(labels = comma)+
    theme_classic(base_size = 16)+annotate("label",x=130,y=90, label = "text" )
  </code></pre>
  
  <p>I have added a label but I would like to know if there are other shapes -maybe colored- in which I could put the text. Ideally an arrow but also the label with the text and the arrow below.
  <a href="https://i.stack.imgur.com/Tnbf7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Tnbf7.png" alt="enter image description here"></a></p>