message: improve comment on new `unhandled_finalized` collection
diff: @@ -188,7 +188,9 @@ where
  struct BlockProposerReady {
  /// Set of deploys currently stored in the block proposer.
  sets: BlockProposerDeploySets,
  - /// "Unhandled" deploys are deploys that the BlockProposer have not yet been seen.
  + /// `unhandled_finalized` is a set of hashes for deploys that the `BlockProposer` has not yet
  + /// seen but were reported as reported to `finalized_deploys()`. They are used to
  + /// filter deploys for proposal, similar to `self.sets.finalized_deploys`.
  unhandled_finalized: HashSet<DeployHash>,
  // We don't need the whole Chainspec here, just the deploy config.
  deploy_config: DeployConfig,
  