title: Make plotly annotation font bold
body: <p>I'd like to add <code>annotation</code> to a <code>scatter</code> plot generated by <code>R</code>'s <code>plotly</code> package, and have the text appear in bold.</p>
  
  <p>I'm trying:</p>
  
  <pre><code>library(plotly)
  library(dplyr)
  
  set.seed(1)
  df &lt;- data.frame(x=rnorm(10),y=rnorm(10))
  plotly::plot_ly(x =~ df$x, y =~ df$y,marker = list(size=12), type = 'scatter',mode = "markers") %&gt;%
    plotly::add_annotations(text=1:10,showarrow=T,arrowhead=1,x=df$x,y=df$y,font=list(size=10))
  </code></pre>
  
  <p>Which gives:
  <a href="https://i.stack.imgur.com/wDoLZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/wDoLZ.png" alt="enter image description here"></a></p>
  
  <p>Trying to add <code>face="bold"</code> to the <code>font</code> specification <code>list</code>:</p>
  
  <pre><code>plotly::plot_ly(x =~ df$x, y =~ df$y,marker = list(size=12), type = 'scatter',mode = "markers") %&gt;%
    plotly::add_annotations(text=1:10,showarrow=T,arrowhead=1,x=df$x,y=df$y,font=list(size=10,face="bold"))
  </code></pre>
  
  <p>Doesn't really change anything:
  <a href="https://i.stack.imgur.com/Sfh5Q.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Sfh5Q.png" alt="enter image description here"></a></p>
  
  <p>So the question is how to get that text annotation to appear in bold.</p>
  
  <p>P.S.
  In my real data I'd like to annotate clusters of points hence the annotations come as a separate layer.</p>