access document permalink attribute efficiently (#6740)
access document permalink attribute efficiently (#6740)

Merge pull request 6740
x-way/jekyll,Strangehill/jekyll,x-way/jekyll,fulldecent/jekyll,ryanshaw/jekyll,ryanshaw/jekyll,Strangehill/jekyll,yhironaka/yhironaka.github.io,tillgrallert/jekyll,jekyll/jekyll,getandpost/jekyll.github.io,tillgrallert/jekyll,tillgrallert/jekyll,getandpost/jekyll.github.io,Strangehill/jekyll,x-way/jekyll,chrisfinazzo/jekyll,jaybe-jekyll/jekyll,fulldecent/jekyll,ryanshaw/jekyll,Strangehill/jekyll,chrisfinazzo/jekyll,getandpost/jekyll.github.io,jaybe-jekyll/jekyll,fulldecent/jekyll,chrisfinazzo/jekyll,jekyll/jekyll,jaybe-jekyll/jekyll,x-way/jekyll,ryanshaw/jekyll,tillgrallert/jekyll,tillgrallert/jekyll,chrisfinazzo/jekyll,jaybe-jekyll/jekyll,jekyll/jekyll,jekyll/jekyll,Strangehill/jekyll,fulldecent/jekyll