fixed link to themes documentation in README
fixed link to themes documentation in README

VukDukic/cleaver,dapperAuteur/cleaver,moreati/cleaver,VukDukic/cleaver,scalp42/cleaver,gnclmorais/cleaver,noamtamim/cleaver,codeheroics/cleaver,codeheroics/cleaver,gnclmorais/cleaver,teazean/cleaver,adriens/cleaver,sjaakvandenberg/cleaver,sjaakvandenberg/cleaver,hugo-agbonon/cleaver,jdan/cleaver,jdan/cleaver,teazean/cleaver,moreati/cleaver,scalp42/cleaver,dapperAuteur/cleaver,hugo-agbonon/cleaver,noamtamim/cleaver,nuno-silva18/cleaver,adriens/cleaver,nuno-silva18/cleaver