docs consistent with Dataset constructor taking variables
docs consistent with Dataset constructor taking variables

markelg/xray,jhamman/xarray,drewokane/xray,xray/xray,shoyer/xarray,pydata/xarray,rabernat/xray,jhamman/xarray,chunweiyuan/xarray,shoyer/xarray,rabernat/xray,jhamman/xray,pydata/xarray,shoyer/xray,markelg/xray,pydata/xarray,jhamman/xarray,jcmgray/xarray,NicWayand/xray,markelg/xray