release(go-redis): v9.9.0

[ndyakov]

• Add release notes
• Update dependencies and version.go

[Copilot]

Pull Request Overview

This PR prepares the v9.9.0 release by updating version numbers, dependency versions across multiple go.mod files, and adding detailed release notes.

• Updated the version returned in version.go from "9.8.0" to "9.9.0".
• Updated dependency versions from v9.8.0 to v9.9.0 in various module files.
• Added release notes describing new features, bug fixes, and improvements for v9.9.0.

Reviewed Changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
version.go	Updated release version to "9.9.0".
extra/redisprometheus/go.mod	Updated redis dependency version to v9.9.0.
extra/redisotel/go.mod	Updated redis and rediscmd dependency versions to v9.9.0.
extra/rediscmd/go.mod	Updated redis dependency version to v9.9.0.
extra/rediscensus/go.mod	Updated redis and rediscmd dependency versions to v9.9.0.
example/scan-struct/go.mod	Updated redis dependency version to v9.9.0.
example/redis-bloom/go.mod	Updated redis dependency version to v9.9.0.
example/otel/go.mod	Updated redis and rediscmd dependency versions to v9.9.0.
example/lua-scripting/go.mod	Updated redis dependency version to v9.9.0.
example/hset-struct/go.mod	Updated redis dependency version to v9.9.0.
example/hll/go.mod	Updated redis dependency version to v9.9.0.
example/del-keys-without-ttl/go.mod	Updated redis dependency version to v9.9.0.
RELEASE-NOTES.md	Added release notes for v9.9.0 with detailed feature and fix info.