title: How to italicize one category in a legend in ggplot2
body: <p>For my legend in ggplot2 I have 2 categories, how do I italicize only 1 category and not the other? </p>
  
  <p>As an example, consider the following plot. How can I set "Manual" in italics?</p>
  
  <pre class="lang-r prettyprint-override"><code>library(ggplot2)
  
  ggplot(data = mtcars, aes(x = as.factor(am), fill = as.factor(am))) + 
    geom_bar() + 
    scale_fill_discrete(
      "Transmission",
      breaks = c(0, 1),
      labels = c("Automatic", "Manual")
    )
  </code></pre>
  
  <p><img src="https://i.imgur.com/ZOpTxC3.png" alt=""></p>
  
  <p><sup>Created on 2020-01-01 by the <a href="https://reprex.tidyverse.org" rel="noreferrer">reprex package</a> (v0.3.0)</sup></p>