updated some doc tests in raster
updated some doc tests in raster

csherwood-usgs/landlab,SiccarPoint/landlab,cmshobe/landlab,ManuSchmi88/landlab,laijingtao/landlab,amandersillinois/landlab,csherwood-usgs/landlab,cmshobe/landlab,landlab/landlab,RondaStrauch/landlab,Carralex/landlab,landlab/landlab,cmshobe/landlab,SiccarPoint/landlab,RondaStrauch/landlab,Carralex/landlab,ManuSchmi88/landlab,RondaStrauch/landlab,ManuSchmi88/landlab,laijingtao/landlab,landlab/landlab,amandersillinois/landlab,Carralex/landlab