message: Improve log messages in the `LinearChainSync`.
diff: @@ -302,12 +302,22 @@ impl<I: Clone + PartialEq + 'static> LinearChainSync<I> {
  "Block execution result doesn't match received block."
  );
  if self.is_recent_block(&block) {
  - info!("downloaded recent block. finished synchronization");
  + info!(
  + hash=?block.hash(),
  + height=?block.header().height(),
  + era=?block.header().era_id(),
  + "downloaded recent block. finished synchronization"
  + );
  self.mark_done();
  return Effects::new();
  }
  if self.is_currently_active_era(&maybe_switch_block) {
  - info!("downloaded block from a new era. finished synchronization");
  + info!(
  + hash=?block.hash(),
  + height=?block.header().height(),
  + era=?block.header().era_id(),
  + "downloaded switch block of a new era. finished synchronization"
  + );
  self.mark_done();
  return Effects::new();
  }
  