Optimize path sanitization of default front matter (#8154)
Optimize path sanitization of default front matter (#8154)

Merge pull request 8154
fulldecent/jekyll,x-way/jekyll,ryanshaw/jekyll,x-way/jekyll,ryanshaw/jekyll,x-way/jekyll,x-way/jekyll,jaybe-jekyll/jekyll,jaybe-jekyll/jekyll,chrisfinazzo/jekyll,chrisfinazzo/jekyll,jaybe-jekyll/jekyll,jaybe-jekyll/jekyll,jekyll/jekyll,fulldecent/jekyll,ryanshaw/jekyll,chrisfinazzo/jekyll,fulldecent/jekyll,jekyll/jekyll,yhironaka/yhironaka.github.io,jekyll/jekyll,chrisfinazzo/jekyll,jekyll/jekyll,fulldecent/jekyll,ryanshaw/jekyll