another rev2 -> rev3

web/index.html

@@ -94,7 +94,7 @@ The latest xv6 is <a href="xv6-rev3.tar.gz">xv6-rev3.tar.gz</a>.
 We distribute the sources in electronic form but also as
 a printed booklet with line numbers that keep everyone
 together during lectures.  The booklet is available as
-<a href="xv6-rev2.pdf">xv6-rev3.pdf</a>.
+<a href="xv6-rev3.pdf">xv6-rev3.pdf</a>.
 The xv6 source code is licensed under the traditional <a href="http://www.opensource.org/licenses/mit-license.php">MIT license</a>;
 see the LICENSE file in the source distribution.
 <br><br>