Address PR comments

Author: utpilla

opentelemetry/CHANGELOG.md

@@ -6,7 +6,7 @@
 
 - [#1623](https://github.com/open-telemetry/opentelemetry-rust/pull/1623) Add global::meter_provider_shutdown
 - [#1640](https://github.com/open-telemetry/opentelemetry-rust/pull/1640) Add `PropagationError`
-- [#1701](https://github.com/open-telemetry/opentelemetry-rust/pull/1701) Stabilize `Gauge`
+- [#1701](https://github.com/open-telemetry/opentelemetry-rust/pull/1701) `Gauge` no longer requires `otel-unstable` feature flag, as OpenTelemetry specification for `Gauge` instrumentation is stable.
 
 ### Removed