doc/go1.2.html: add a "New packages" section similar to

http://golang.org/doc/go1.1#new_packages

R=r
CC=golang-dev
https://golang.org/cl/13368053

doc/go1.2.html

@@ -530,6 +530,23 @@ map are unaffected because the associated function map will override the new
 default function definitions.
 </p>
 
+<h3 id="new_packages">New packages</h3>
+
+<p>
+There are two new packages.
+</p>
+
+<ul>
+<li>
+The <a href="/pkg/encoding/"><code>encoding</code></a> package is
+<a href="#encoding">described above</a>.
+</li>
+<li>
+The <a href="/pkg/image/color/palette/"><code>image/color/palette</code></a> package
+provides standard color palettes.
+</li>
+</ul>
+
 <h3 id="minor_library_changes">Minor changes to the library</h3>
 
 <p>