doc/docs: fix broken links

R=golang-dev
CC=golang-dev
https://golang.org/cl/5539076

doc/docs.html

@@ -93,8 +93,8 @@ Notable articles from the <a href="http://blog.golang.org/">Go Blog</a>.
 <h3>Packages</h3>
 
 <ul>
-<li><a href="http://blog.golang.org/2011/01/json-and-go.html">JSON and Go</a> - using the <a href="/pkg/json/">json</a> package.</li>
-<li><a href="http://blog.golang.org/2011/03/gobs-of-data.html">Gobs of data</a> - the design and use of the <a href="/pkg/gob/">gob</a> package.</li>
+<li><a href="http://blog.golang.org/2011/01/json-and-go.html">JSON and Go</a> - using the <a href="/pkg/encoding/json/">json</a> package.</li>
+<li><a href="http://blog.golang.org/2011/03/gobs-of-data.html">Gobs of data</a> - the design and use of the <a href="/pkg/encoding/gob/">gob</a> package.</li>
 <li><a href="http://blog.golang.org/2011/09/laws-of-reflection.html">The Laws of Reflection</a> - the fundamentals of the <a href="/pkg/reflect/">reflect</a> package.</li>
 <li><a href="http://blog.golang.org/2011/09/go-image-package.html">The Go image package</a> - the fundamentals of the <a href="/pkg/image/">image</a> package.</li>
 <li><a href="http://blog.golang.org/2011/09/go-imagedraw-package.html">The Go image/draw package</a> - the fundamentals of the <a href="/pkg/image/draw/">image/draw</a> package.</li>