changelog: add missing entry in doc string for _instrument in opentelemetry-instrumentation-redis

Author: nhtgl

CHANGELOG.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Fixed
+- `opentelemetry-instrumentation-redis` Add missing entry in doc string for `def _instrument`
+  ([#3247](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3247))
+
 ## Version 1.30.0/0.51b0 (2025-02-03)
 
 ### Added