Add some sweet godoc for this bad boy.

modules/core/04-channel/keeper/upgrade.go

@@ -368,6 +368,10 @@ func (k Keeper) WriteUpgradeAckChannel(ctx sdk.Context, portID, channelID string
 	emitChannelUpgradeAckEvent(ctx, portID, channelID, channel, upgrade)
 }
 
+// WriteUpgradeConfirmChannel writes a channel which has successfully passed the ChanUpgradeConfirm handshake step.
+// If the channel has no in-flight packets, its state is updated to indicate that flushing has completed. Otherwise, the counterparty upgrade is set
+// and the channel state is left unchanged.
+// An event is emitted for the handshake step.
 func (k Keeper) WriteUpgradeConfirmChannel(ctx sdk.Context, portID, channelID string, counterpartyUpgrade types.Upgrade) {
 	defer telemetry.IncrCounter(1, "ibc", "channel", "upgrade-confirm")