update slider docs
update slider docs

huguangju/element,ElemeFE/element,ElemeFE/element,Raganof/element,baiyaaaaa/element,Leopoldthecoder/element-1,baiyaaaaa/element,Raganof/element,Leopoldthecoder/element-1,huguangju/element,Kingwl/element,Kingwl/element