Update docs for default doctype (now HTML5)
Update docs for default doctype (now HTML5)

Fixes issue #701

webskyer/jade,ilovezy/jade,omixen/jade,ceremcem/jade,illusionfield/jade,pugjs/then-jade,mrotaru/jade,slang800/yade,Laoujin/jade,andreytkachenko/jade,muthhus/jade,mrotaru/jade,Laoujin/jade,Shinchy/jade,rajnishyadav321/jade,Victorgichohi/jade,cgvarela/jade,wavii/jade,jodytate/jade,derbyparty/derby-jade,jjz/jade,magicdawn/jade,flintinatux/jade,webskyer/jade,VeraWei/jade,hnag409/jade,mumaoxi/jade,Mitrend/jade,pugjs/jade,colin-h/jade,martindale/jade,mumaoxi/jade,jadejs/then-jade,VANITAX/jade,martindale/jade,jadejs/then-jade,harp/jade,timmfin/jade,cutsin/jade,modulexcite/jade,derbyparty/derby-jade,gexiaowei/jade,harp/jade,illusionfield/jade,angrilove/jade,ilovezy/jade,pugjs/jade,jjz/jade,muthhus/jade,pugjs/pug,VeraWei/jade,Victorgichohi/jade,Mitrend/jade,angryrobot/jade,cesarmarinhorj/jade,angrilove/jade,VANITAX/jade,bogus34/jade-vfs,pugjs/pug,jodytate/jade,ddopson/jade-coffeescript,angryrobot/jade,ddopson/jade-coffeescript,bogus34/jade-vfs,gdibble/jade,modulexcite/jade,webmasteraxe/jade,coderhaoxin/jade,coderhaoxin/jade,magicdawn/jade,ridixcr/jade,andreytkachenko/jade,pugjs/then-jade,fredyteheranto/jade,rajnishyadav321/jade,nyakto/jade-async,jirengu/jade,gdibble/jade,hnag409/jade,tranhieutt/jade,colin-h/jade,webmasteraxe/jade,nyakto/jade-async,ridixcr/jade,Shinchy/jade,fredyteheranto/jade,cgvarela/jade,tranhieutt/jade,omixen/jade,cutsin/jade,cesarmarinhorj/jade,jirengu/jade,gexiaowei/jade