doc: Minor fix: "ncdu 1.7" -> "ncdu 1.7 and later"
doc: Minor fix: "ncdu 1.7" -> "ncdu 1.7 and later"

piyo/ncdu,sunny256/ncdu,FauxFaux/ncdu,ppetr/ncdu,guns/ncdu,gitkaste/ncdu,rofl0r/ncdu,FauxFaux/ncdu,guns/ncdu,ppetr/ncdu,gitkaste/ncdu,guns/ncdu,sunny256/ncdu,ppetr/ncdu,rofl0r/ncdu