message: Expand the CandidateBlock::timestamp comment.
diff: @@ -36,7 +36,10 @@ impl CandidateBlock {
  &self.proto_block
  }
  - /// Returns the candidate block's timestamp.
  + /// Returns the candidate block's timestamp, i.e. when the block was proposed.
  + ///
  + /// This is idential to the timestamp of the Highway unit, and the timestamp of the `Block`,
  + /// if it gets finalized.
  pub(crate) fn timestamp(&self) -> Timestamp {
  self.timestamp
  }
  