/// Proof that the sender knows the per-commitment secret of the previous commitment transaction.
/// This is used to convince the recipient that the channel is at a certain commitment
/// number even if they lost that data due to a local failure. Of course, the peer may lie
/// Proof that the sender knows the per-commitment secret of the previous commitment transaction.
/// This is used to convince the recipient that the channel is at a certain commitment
/// number even if they lost that data due to a local failure. Of course, the peer may lie