[modify] remove link_target options except "_blank"
[modify] remove link_target options except "_blank"

MasakiInaya/shirasagi,ShinjiTanimoto/shirasagi,shirasagi/shirasagi,shirasagi/shirasagi,MasakiInaya/shirasagi,sunny4381/shirasagi,itowtips/shirasagi,sunny4381/shirasagi,MasakiInaya/shirasagi,tany/ss,ShinjiTanimoto/shirasagi,itowtips/shirasagi,tany/ss,ShinjiTanimoto/shirasagi,ShinjiTanimoto/shirasagi,itowtips/shirasagi,itowtips/shirasagi,shirasagi/shirasagi,tany/ss,sunny4381/shirasagi,shirasagi/shirasagi,tany/ss,MasakiInaya/shirasagi,sunny4381/shirasagi