[improve][doc] Add missing doc for metric pulsar_consumer_msg_ack_rate
@@ -455,6 +455,7 @@ All the consumer metrics are labelled with the following labels:
| pulsar_consumer_unacked_messages | Gauge | The total number of unacknowledged messages of a consumer (messages). |
| pulsar_consumer_blocked_on_unacked_messages | Gauge | Indicate whether a consumer is blocked on unacknowledged messages or not. <br /> <ul><li>1 means the consumer is blocked on waiting unacknowledged messages to be acked.</li><li>0 means the consumer is not blocked on waiting unacknowledged messages to be acked.</li></ul> |
| pulsar_consumer_msg_rate_out | Gauge | The total message dispatch rate for a consumer (message per second). |
+| pulsar_consumer_msg_ack_rate | Gauge | The total rate of message ack (message per second). |
| pulsar_consumer_msg_throughput_out | Gauge | The total message dispatch throughput for a consumer (byte per second). |
| pulsar_consumer_available_permits | Gauge | The available permits for for a consumer. |
