adding hexo-renderer-markdown-it-plus (#520)
adding hexo-renderer-markdown-it-plus (#520)


jack08/static-test,hexojs/site,tnu818/blog.iyu.pub,tnu818/blog.iyu.pub,lucianobarauna/dochexo,KeishaSPerkins/firmly-planted,KeishaSPerkins/firmly-planted,oqyj/hexobg,lucianobarauna/dochexo,jack08/static-test,oqyj/hexobg,pona08/site-static,KeishaSPerkins/firmly-planted,hexojs/site,tnu818/blog.iyu.pub,oqyj/hexobg,pona08/site-static,pona08/site-static,lucianobarauna/dochexo