docs: remove watch option in config (#7940)
docs: remove watch option in config (#7940)

Merge pull request 7940
jekyll/jekyll,jaybe-jekyll/jekyll,yhironaka/yhironaka.github.io,x-way/jekyll,x-way/jekyll,ryanshaw/jekyll,ryanshaw/jekyll,chrisfinazzo/jekyll,jaybe-jekyll/jekyll,fulldecent/jekyll,chrisfinazzo/jekyll,chrisfinazzo/jekyll,fulldecent/jekyll,ryanshaw/jekyll,jekyll/jekyll,chrisfinazzo/jekyll,jekyll/jekyll,x-way/jekyll,jaybe-jekyll/jekyll,fulldecent/jekyll,fulldecent/jekyll,ryanshaw/jekyll,x-way/jekyll,jaybe-jekyll/jekyll,jekyll/jekyll