Docs: `site.url` behavior on development and production environments (#6270)
Docs: `site.url` behavior on development and production environments (#6270)

Merge pull request 6270
ryanshaw/jekyll,getandpost/jekyll.github.io,yhironaka/yhironaka.github.io,gencer/jekyll,ryanshaw/jekyll,x-way/jekyll,chrisfinazzo/jekyll,jaybe-jekyll/jekyll,chrisfinazzo/jekyll,gencer/jekyll,jekyll/jekyll,ryanshaw/jekyll,jekyll/jekyll,Strangehill/jekyll,tillgrallert/jekyll,tillgrallert/jekyll,x-way/jekyll,gencer/jekyll,jaybe-jekyll/jekyll,alex-kovac/jekyll,getandpost/jekyll.github.io,fulldecent/jekyll,x-way/jekyll,alex-kovac/jekyll,jaybe-jekyll/jekyll,tillgrallert/jekyll,fulldecent/jekyll,alex-kovac/jekyll,jekyll/jekyll,gencer/jekyll,getandpost/jekyll.github.io,tillgrallert/jekyll,Strangehill/jekyll,fulldecent/jekyll,ryanshaw/jekyll,x-way/jekyll,gencer/jekyll,Strangehill/jekyll,Strangehill/jekyll,jekyll/jekyll,jaybe-jekyll/jekyll,fulldecent/jekyll,alex-kovac/jekyll,chrisfinazzo/jekyll,tillgrallert/jekyll,alex-kovac/jekyll,chrisfinazzo/jekyll,Strangehill/jekyll