CHANGELOG-3.2: highlight watch client backport

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

CHANGELOG-3.2.md

@@ -7,17 +7,18 @@ Previous change logs can be found at [CHANGELOG-3.1](https://github.com/coreos/e
 
 See [code changes](https://github.com/coreos/etcd/compare/v3.2.22...v3.2.23) and [v3.2 upgrade guide](https://github.com/coreos/etcd/blob/master/Documentation/upgrades/upgrade_3_2.md) for any breaking changes. **Again, before running upgrades from any previous release, please make sure to read change logs below and [v3.2 upgrade guide](https://github.com/coreos/etcd/blob/master/Documentation/upgrades/upgrade_3_2.md).**
 
-### Metrics, Monitoring
-
-- Add [`etcd_server_version`](https://github.com/coreos/etcd/pull/8960) Prometheus metric.
-  - To replace [Kubernetes `etcd-version-monitor`](https://github.com/coreos/etcd/issues/8948).
-
 ### Improved
 
 - Improve [slow request apply warning log](https://github.com/coreos/etcd/pull/9288).
   - e.g. `read-only range request "key:\"/a\" range_end:\"/b\" " with result "range_response_count:3 size:96" took too long (97.966µs) to execute`.
   - Redact [request value field](https://github.com/coreos/etcd/pull/9822).
   - Provide [response size](https://github.com/coreos/etcd/pull/9826).
+- Add [backoff on watch retries on transient errors](https://github.com/coreos/etcd/pull/9840).
+
+### Metrics, Monitoring
+
+- Add [`etcd_server_version`](https://github.com/coreos/etcd/pull/8960) Prometheus metric.
+  - To replace [Kubernetes `etcd-version-monitor`](https://github.com/coreos/etcd/issues/8948).
 
 ### Go