mention `docs` folder to deploy on GitHub Pages
mention `docs` folder to deploy on GitHub Pages

fix #5543
xiebinhqy/jklly_china,gencer/jekyll,alex-kovac/jekyll,jaybe-jekyll/jekyll,ryanshaw/jekyll,darwin/jekyll,rlugojr/jekyll,x-way/jekyll,Strangehill/jekyll,fulldecent/jekyll,getandpost/jekyll.github.io,jaybe-jekyll/jekyll,tomjohnson1492/jekyll,xiebinhqy/jklly_china,Strangehill/jekyll,tillgrallert/jekyll,rasa2011/rasa2011.github.io,jekyll/jekyll,tomjohnson1492/jekyll,rasa2011/rasa2011.github.io,ryanshaw/jekyll,alfredxing/jekyll,chrisfinazzo/jekyll,gencer/jekyll,alfredxing/jekyll,ZDroid/jekyll,getandpost/jekyll.github.io,xiebinhqy/jklly_china,tillgrallert/jekyll,xiebinhqy/jklly_china,chrisfinazzo/jekyll,darwin/jekyll,ZDroid/jekyll,jekyll/jekyll,alex-kovac/jekyll,tillgrallert/jekyll,x-way/jekyll,fulldecent/jekyll,chrisfinazzo/jekyll,getandpost/jekyll.github.io,alex-kovac/jekyll,tomjohnson1492/jekyll,rasa2011/rasa2011.github.io,ryanshaw/jekyll,darwin/jekyll,gencer/jekyll,ZDroid/jekyll,yhironaka/yhironaka.github.io,rlugojr/jekyll,ryanshaw/jekyll,jekyll/jekyll,tomjohnson1492/jekyll,alfredxing/jekyll,jaybe-jekyll/jekyll,jekyll/jekyll,tomjohnson1492/jekyll,Strangehill/jekyll,tillgrallert/jekyll,rlugojr/jekyll,gencer/jekyll,Strangehill/jekyll,rlugojr/jekyll,alex-kovac/jekyll,alfredxing/jekyll,fulldecent/jekyll,jaybe-jekyll/jekyll,darwin/jekyll,alex-kovac/jekyll,x-way/jekyll,tillgrallert/jekyll,Strangehill/jekyll,chrisfinazzo/jekyll,gencer/jekyll,x-way/jekyll,fulldecent/jekyll