Simplify changelog per PR feedback.

Author: michaelsafyan

instrumentation-genai/opentelemetry-instrumentation-google-genai/CHANGELOG.md

@@ -8,9 +8,4 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## Unreleased
 
 Create an initial version of Open Telemetry instrumentation for github.com/googleapis/python-genai.
-
-This version adds support for instrumenting `Client.models.generate_content` but does not yet support
-instrumentation for streaming and async use cases.
-
-This version supports some of the `gen_ai.request.*` span attributes but does not cover all of the
-GenAI semantic conventions for spans that are applicable just yet.
+([#3256](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3256))