config: add channel commit interval parameter

sample-lnd.conf

@@ -264,6 +264,11 @@
 ; for the channel closure is not set.
 ; coop-close-target-confs=10
 
+; The maximum time that is allowed to pass between receiving a channel state
+; update and signing the next commitment. Setting this to a longer duration
+; allows for more efficient channel operations at the cost of latency.
+; channel-commit-interval=50ms
+
 ; 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.