client: fix doc typo
// func etcdDial(c *clientv3.Client, service string) (*grpc.ClientConn, error) {
// etcdResolver, err := resolver.NewBuilder(c);
// if err { return nil, err }
-// return grpc.Dial("etc://foo", grpc.WithResolvers(etcdResolver))
+// return grpc.Dial("etcd://foo", grpc.WithResolvers(etcdResolver))
// }
//
// Optionally, force delete an endpoint:
