Check if site is in incremental mode optimally (#8401)
Check if site is in incremental mode optimally (#8401)

Merge pull request 8401
jaybe-jekyll/jekyll,fulldecent/jekyll,jekyll/jekyll,chrisfinazzo/jekyll,x-way/jekyll,jekyll/jekyll,chrisfinazzo/jekyll,jekyll/jekyll,fulldecent/jekyll,jaybe-jekyll/jekyll,x-way/jekyll,ryanshaw/jekyll,jaybe-jekyll/jekyll,ryanshaw/jekyll,ryanshaw/jekyll,jekyll/jekyll,x-way/jekyll,jaybe-jekyll/jekyll,ryanshaw/jekyll,chrisfinazzo/jekyll,chrisfinazzo/jekyll,fulldecent/jekyll,x-way/jekyll,fulldecent/jekyll