app: use https instead of protocol-relative URLs

Protocol-relative URLs (//blog.golang.org/...) are redundant, we use
HTTPS everywhere.
Use the https:// scheme instead.

Updates golang/go#17961.

Change-Id: I710959584971f1fa155bab3ea623c33a9f6ab9e9
Reviewed-on: https://go-review.googlesource.com/37884
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/app/goplay/edit.html b/app/goplay/edit.html
index f4229fb..7e240b4 100644
--- a/app/goplay/edit.html
+++ b/app/goplay/edit.html
@@ -3,7 +3,7 @@
 	<head>
 		<title>The Go Playground</title>
 		<link rel="stylesheet" href="/static/style.css">
-		<script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
+		<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
 		<script src="/static/jquery-linedtextarea.js"></script>
 		<script src="/playground.js"></script>
 		<script src="/static/playground-embed.js"></script>
@@ -117,7 +117,7 @@
 
 <p>
 The Go Playground is a web service that runs on
-<a href="//golang.org/">golang.org</a>'s servers.
+<a href="https://golang.org/">golang.org</a>'s servers.
 The service receives a Go program, compiles, links, and
 runs the program inside a sandbox, then returns the output.
 </p>
@@ -147,7 +147,7 @@
 </ul>
 
 <p>
-The article "<a href="//blog.golang.org/playground" target="_blank">Inside
+The article "<a href="https://blog.golang.org/playground" target="_blank">Inside
 the Go Playground</a>" describes how the playground is implemented.
 </p>
 
@@ -158,7 +158,7 @@
 
 <p>
 The playground service is used by more than just the official Go project
-(<a href="//gobyexample.com/">Go by Example</a> is one other instance)
+(<a href="https://gobyexample.com/">Go by Example</a> is one other instance)
 and we are happy for you to use it on your own site.
 All we ask is that you
 <a href="mailto:golang-dev@googlegroups.com">contact us first (note this is a public mailing list)</a>,