Update plugin docs, especially webroot for -w
Update plugin docs, especially webroot for -w

lmcro/letsencrypt,lmcro/letsencrypt,bsmr-misc-forks/letsencrypt,brentdax/letsencrypt,xgin/letsencrypt,thanatos/lets-encrypt-preview,dietsche/letsencrypt,kuba/letsencrypt,jtl999/certbot,mitnk/letsencrypt,TheBoegl/letsencrypt,wteiken/letsencrypt,mitnk/letsencrypt,VladimirTyrin/letsencrypt,jtl999/certbot,goofwear/letsencrypt,piru/letsencrypt,piru/letsencrypt,mrb/letsencrypt,dietsche/letsencrypt,jsha/letsencrypt,kuba/letsencrypt,twstrike/le_for_patching,lbeltrame/letsencrypt,martindale/letsencrypt,VladimirTyrin/letsencrypt,Sveder/letsencrypt,twstrike/le_for_patching,TheBoegl/letsencrypt,wteiken/letsencrypt,DavidGarciaCat/letsencrypt,stweil/letsencrypt,mrb/letsencrypt,lbeltrame/letsencrypt,bsmr-misc-forks/letsencrypt,letsencrypt/letsencrypt,DavidGarciaCat/letsencrypt,martindale/letsencrypt,xgin/letsencrypt,goofwear/letsencrypt,thanatos/lets-encrypt-preview,letsencrypt/letsencrypt,jsha/letsencrypt,brentdax/letsencrypt,Sveder/letsencrypt,stweil/letsencrypt