title: Difference in using TextBlock and FontIcon (when used outside AppBarButton)
body: <p>For placing a font based icon in UI, what is the difference between  </p>
  
  <pre><code>&lt;TextBlock FontFamily="Segoe MDL2 Assets"
             Text="&amp;#xE122;" /&gt;  
  </code></pre>
  
  <p>and  </p>
  
  <pre><code>&lt;FontIcon FontFamily="Segoe MDL2 Assets"
            Glyph="&amp;#xE122;" /&gt;
  </code></pre>
  
  <p>Which one should be preferred and why?</p>