Mention .Params and .Page variables in shortcode docs. Also `highlight` variables.
Mention .Params and .Page variables in shortcode docs. Also `highlight` variables.

tubo028/hugo,ffrizzo/hugo,mitchchn/hugo,anthonyfok/hugo,tatsushid/hugo,mayah/hugo,jygastaud/hugo,fedelibre/hugo,jygastaud/hugo,halostatue/hugo,Zenithar/hugo,gohugoio/hugo,badoet/hugo,coderzh/hugo,ryanclarke/hugo,soundrussian/hugo,coderzh/hugo,kujohn/hugo,badoet/hugo,derekperkins/hugo,mdhender/hugo,fhergomez/hugo,gohugoio/hugo,kujohn/hugo,bogem/hugo,mdhender/hugo,anthonyfok/hugo,tjyang/hugo,tatsushid/hugo,ryanclarke/hugo,fedelibre/hugo,tischda/hugo,sprig/hugo,tjyang/hugo,digitalcraftsman/hugo,ifraixedes/hugo,fedelibre/hugo,mitchchn/hugo,fedelibre/hugo,anthonyfok/hugo,gohugoio/hugo,abourget/hugo,fhergomez/hugo,soundrussian/hugo,ffrizzo/hugo,bogem/hugo,tischda/hugo,melo/hugo,melo/hugo,sprig/hugo,MarkDBlackwell/hugo,vbatoufflet/hugo,abourget/hugo,derekperkins/hugo,mayah/hugo,digitalcraftsman/hugo,mdhender/hugo,halostatue/hugo,bramp/hugo,vbatoufflet/hugo,ifraixedes/hugo,Zenithar/hugo,tubo028/hugo,MarkDBlackwell/hugo,bramp/hugo,mdhender/hugo