title: Greek letter in ggtitle will not become italic bold in r
body: <p><a href="https://i.stack.imgur.com/jj1wG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jj1wG.png" alt="the tau symbol is not bold italic like the rest of the title" /></a></p>
  <pre><code>plot19 &lt;- ggplot(FoBlandAlt.apex, aes(x = avg, y = perc)) +
    geom_point(size=2, alpha = 0.5) +
    geom_hline(yintercept = percent_mean_diff) +
    geom_hline(yintercept = lower.perc, color = &quot;black&quot;, linetype=&quot;dashed&quot;) +
    geom_hline(yintercept = upper.perc, color = &quot;black&quot;, linetype=&quot;dashed&quot;) +
    ggtitle(expression(bolditalic(tau~(s) ~~STATSports))) +
    ylab(&quot;Difference from Criterion&quot;) +
    xlab(&quot;Mean&quot;)+theme_light()+
    theme(
      axis.title.y = element_text(color = &quot;black&quot;, size=10),
      axis.title.x = element_text(color = &quot;black&quot;, size=10),
      title = element_text(color= &quot;black&quot;, size = 6, face = &quot;bold.italic&quot;)
    )
  </code></pre>
  <p>I have the title set up the way I want, but for some reason the tau symbol (τ) wont turn bolditalic like the rest of the text</p>