fix custom router line in router docs
fix custom router line in router docs

catalpainternational/rapidsms,catalpainternational/rapidsms,eHealthAfrica/rapidsms,caktus/rapidsms,ehealthafrica-ci/rapidsms,catalpainternational/rapidsms,peterayeni/rapidsms,ehealthafrica-ci/rapidsms,ehealthafrica-ci/rapidsms,peterayeni/rapidsms,caktus/rapidsms,eHealthAfrica/rapidsms,catalpainternational/rapidsms,peterayeni/rapidsms,caktus/rapidsms,lsgunth/rapidsms,lsgunth/rapidsms,peterayeni/rapidsms,eHealthAfrica/rapidsms,lsgunth/rapidsms,lsgunth/rapidsms