/// Returns transactions that must be monitored for reorganization out of the chain along
/// with the hash of the block as part of which it had been previously confirmed.
///
+ /// Note that the returned `Option<BlockHash>` might be `None` for channels created with LDK
+ /// 0.0.112 and prior, in which case you need to manually track previous confirmations.
+ ///
/// Will include any transactions passed to [`transactions_confirmed`] that have insufficient
/// confirmations to be safe from a chain reorganization. Will not include any transactions
/// passed to [`transaction_unconfirmed`], unless later reconfirmed.