config: add channel commit batch size parameter

sample-lnd.conf

@@ -269,6 +269,10 @@
 ; allows for more efficient channel operations at the cost of latency.
 ; channel-commit-interval=50ms
 
+; The maximum number of channel state updates that is accumulated before signing
+; a new commitment.
+; channel-commit-batch-size=10
+
 ; The default max_htlc applied when opening or accepting channels. This value
 ; limits the number of concurrent HTLCs that the remote party can add to the
 ; commitment. The maximum possible value is 483.