title: \frac{}{} doesn't work in plt.text?
body: <p>I am trying to add a text to my plot, using latex. Latex and \frac{}{} works well in titles and labels, but I can not get it work in plt.text(). I tried both, using raw or double backslash.</p>
  
  <pre><code>import matplotlib.pyplot as plt
  
  plt.axhline(x=30, c='k')
  plt.text(0,0,r'$\frac{\Gamma_M}{\Gamma_D}$ = 10')
  plt.xlabel(r'$\frac{\Gamma_M}{\Gamma_D}$')
  </code></pre>
  
  <p>It works for label (if you outcomment text line) but not for text, gives me this output:</p>
  
  <pre><code>KeyError: '\\Gamma_M'
  </code></pre>