godoc: fetch jQuery via https

R=rsc, bradfitz
CC=golang-dev
https://golang.org/cl/6614064

lib/godoc/godoc.html

@@ -8,7 +8,7 @@
   <title>The Go Programming Language</title>
 {{end}}
 <link type="text/css" rel="stylesheet" href="/doc/style.css">
-<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
+<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
 <script type="text/javascript">window.jQuery || document.write(unescape("%3Cscript src='/doc/jquery.js' type='text/javascript'%3E%3C/script%3E"));</script>
 <script type="text/javascript" src="/doc/godocs.js"></script>
 {{if .SearchBox}}