title: matplotlib text underline
body: <p>I am trying to add underline to one of the character in plt.text.</p>
  
  <pre><code>plt.text(.5,.5,r'\underline{O}H')
  </code></pre>
  
  <p>This does not seem to work, I tried to use <code>\overline{O}</code>, which works just fine. I also tried <code>plt.rc('text',usetex=True)</code> even this does not seem to work. </p>
  
  <p>Please help me get underline for a text in matplitlib. </p>