add DetachmentLtdErosion to docs
add DetachmentLtdErosion to docs

was missing, but in release

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