message: bench: Rename throughput benchmark groups to `age`
  They are benchmarking the entire age protocol, not just STREAM.
diff: @@ -13,7 +13,7 @@ const KB: usize = 1024;
  fn bench(c: &mut Criterion<CyclesPerByte>) {
  let identity = x25519::Identity::generate();
  let recipient = identity.to_public();
  - let mut group = c.benchmark_group("stream");
  + let mut group = c.benchmark_group("age");
  // Prepare buffers to use in the benchmarks.
  let pt_buf = vec![7u8; 1024 * KB];
  