Manually fixing markup on main page

Real fix is at matplotlib/matplotlib#3543

Author: tacaswell

index.html

@@ -152,9 +152,9 @@ <h1>Introduction</h1>
   For a sampling, see the <a href="users/screenshots.html">screenshots</a>, <a href="gallery.html">thumbnail</a> gallery,  and
     <a href="examples/index.html">examples</a> directory</p>
 
-<p>For simple plotting the <pre>pyplot</pre> interface provides a
+<p>For simple plotting the <tt>pyplot</tt> interface provides a
   MATLAB-like interface, particularly when combined
-  with <pre>IPython</pre>.  For the power user, you have full control
+  with <tt>IPython</tt>.  For the power user, you have full control
   of line styles, font properties, axes properties, etc, via an object
   oriented interface or via a set of functions familiar to MATLAB
   users.</p>
@@ -303,4 +303,4 @@ <h1>Open source</h1>
     </div>
 
 </body>
-</html>
+</html>