remove extra line from rolling doc string
remove extra line from rolling doc string

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