message: nydusctl: refine nydusctl general information print messages
diff: @@ -401,31 +401,28 @@ Commit: {git_commit}
  if let Some(b) = i.get("backend_collection") {
  if let Some(fs_backends) = b.as_object() {
  if !fs_backends.is_empty() {
  - println!("Backend list:")
  + println!("Instances:")
  }
  for (mount_point, backend_obj) in fs_backends {
  let backend: FsBackendDesc =
  serde_json::from_value(backend_obj.clone()).unwrap();
  - println!(" {}", mount_point);
  - println!(" type: {}", backend.backend_type);
  - println!(" mountpoint: {}", backend.mountpoint);
  - println!(" mounted_time: {}", backend.mounted_time);
  + println!("\tInstance Mountpoint: {}", mount_point);
  + println!("\tType: {}", backend.backend_type);
  + println!("\tMounted Time: {}", backend.mounted_time);
  match backend.backend_type {
  FsBackendType::PassthroughFs => {}
  FsBackendType::Rafs => {
  let cfg = backend.config.unwrap();
  let cache_cfg = cfg.get_cache_config()?;
  let rafs_cfg = cfg.get_rafs_config()?;
  + print!("\tMode: {}", rafs_cfg.mode);
  + print!("\tPrefetch: {}", cache_cfg.prefetch.enable);
  print!(
  - r#" Mode: {meta_mode}
  - Prefetch: {enabled}
  - Prefetch Merging Size: {merging_size}
  - "#,
  - meta_mode = rafs_cfg.mode,
  - enabled = cache_cfg.prefetch.enable,
  - merging_size = cache_cfg.prefetch.batch_size,
  + "\tPrefetch Merging Size: {}",
  + cache_cfg.prefetch.batch_size
  );
  + print!("")
  }
  }
  }
  