html/template: update security model link

Fixes #16148.

Change-Id: Ifab773e986b768602476824d005eea9200761236
Reviewed-on: https://go-review.googlesource.com/24327
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>

src/html/template/doc.go

@@ -166,7 +166,7 @@ that would have been produced if {{.}} was a regular string.
 
 Security Model
 
-http://js-quasis-libraries-and-repl.googlecode.com/svn/trunk/safetemplate.html#problem_definition defines "safe" as used by this package.
+https://rawgit.com/mikesamuel/sanitized-jquery-templates/trunk/safetemplate.html#problem_definition defines "safe" as used by this package.
 
 This package assumes that template authors are trusted, that Execute's data
 parameter is not, and seeks to preserve the properties below in the face