f - Simplify FeeRateAdjustmentError match in tx_init_rbf acceptor path

Same simplification as the splice_init path: collapse 3 Err arms into
2 by relying on the Display impl for behavioral suffixes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jkczyz

lightning/src/ln/channel.rs

@@ -12552,17 +12552,6 @@ where
 			Some(c) => {
 				match c.net_value_for_acceptor_at_feerate(feerate, holder_balance.unwrap()) {
 					Ok(net_value) => Some(net_value),
-					Err(e @ FeeRateAdjustmentError::FeeRateTooLow { .. }) => {
-						log_info!(
-								logger,
-								"Initiator's RBF feerate ({}) for channel {} is below our minimum: {}; \
-								 proceeding without queued contribution, will RBF later",
-								feerate,
-								self.context.channel_id(),
-								e,
-							);
-						None
-					},
 					Err(e @ FeeRateAdjustmentError::FeeRateTooHigh { .. }) => {
 						return Err(ChannelError::WarnAndDisconnect(format!(
 							"Cannot accommodate initiator's RBF feerate ({}) for channel {}: {}",
@@ -12571,14 +12560,10 @@ where
 							e,
 						)));
 					},
-					Err(
-						e @ FeeRateAdjustmentError::FeeBufferInsufficient { .. }
-						| e @ FeeRateAdjustmentError::FeeBufferOverflow { .. },
-					) => {
+					Err(e) => {
 						log_info!(
 							logger,
-							"Cannot accommodate initiator's RBF feerate ({}) for channel {}: {}; \
-								 proceeding without contribution",
+							"Cannot accommodate initiator's RBF feerate ({}) for channel {}: {}",
 							feerate,
 							self.context.channel_id(),
 							e,