title: Change geom_text to bold when parse=TRUE
body: <p>I am annotating faceted plots to include a superscript, yet am having trouble making the text bold. I realise that this has something to do with creating an <code>expression</code> outside the plot call and then specifying <code>parse=TRUE</code>. There is probably quite a simple solution but so far nothing I have tried has worked, including the use of <code>bquote()</code> and <code>bold()</code>. Thanks</p>
  
  <pre><code>library(ggplot2)
  
  data(iris)
  
  rsq&lt;-c(.3,.6,.75)
  pos&lt;-c(5,6,7)
  Species&lt;-levels(iris$Species)
  
  big_data&lt;-as.data.frame(cbind(pos, rsq))
  big_data$Species&lt;-Species
  
  lab &lt;- paste("r^2 == ", round(big_data$rsq,2))
  
  ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width)) +
    facet_wrap(~Species,scales='free_x')+
    geom_point(size=3,show.legend = F) +
    geom_text(aes(x=pos,y=1,label=as.character(lab)),parse=TRUE,data=big_data,fontface='bold')
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/EDa70.png" rel="noreferrer"><img src="https://i.stack.imgur.com/EDa70.png" alt="enter image description here"></a></p>