Replace `String#=~` with `String#match?` (#7718)
Replace `String#=~` with `String#match?` (#7718)

Merge pull request 7718
fulldecent/jekyll,x-way/jekyll,Strangehill/jekyll,chrisfinazzo/jekyll,Strangehill/jekyll,tillgrallert/jekyll,x-way/jekyll,chrisfinazzo/jekyll,fulldecent/jekyll,chrisfinazzo/jekyll,ryanshaw/jekyll,jaybe-jekyll/jekyll,tillgrallert/jekyll,ryanshaw/jekyll,fulldecent/jekyll,tillgrallert/jekyll,chrisfinazzo/jekyll,fulldecent/jekyll,x-way/jekyll,jaybe-jekyll/jekyll,jaybe-jekyll/jekyll,ryanshaw/jekyll,x-way/jekyll,yhironaka/yhironaka.github.io,tillgrallert/jekyll,jaybe-jekyll/jekyll,jekyll/jekyll,jekyll/jekyll,jekyll/jekyll,Strangehill/jekyll,jekyll/jekyll,ryanshaw/jekyll,Strangehill/jekyll,Strangehill/jekyll,tillgrallert/jekyll