multi: fix fmt.Errorf error wrapping

Refactor fmt.Errorf usage to correctly wrap errors instead of using
non-wrapping format verbs.

lnrpc/neutrinorpc/neutrino_server.go

@@ -198,7 +198,7 @@ func (s *Server) Status(ctx context.Context,
 
 	bestBlock, err := s.cfg.NeutrinoCS.BestBlock()
 	if err != nil {
-		return nil, fmt.Errorf("could not get best block: %v", err)
+		return nil, fmt.Errorf("could not get best block: %w", err)
 	}
 
 	peers := s.cfg.NeutrinoCS.Peers()