title: Why doesn't ToUpper() return "*" when applied to "8"?
body: <pre><code>string s = "h";
  s = s.ToUpper();
  </code></pre>
  
  <p>returns <code>"H"</code>.</p>
  
  <pre><code>string s = "8";
  s = s.ToUpper();
  </code></pre>
  
  <p>returns <code>"8"</code></p>
  
  <p>Should this not return <code>"*"</code>?</p>