[Issue]: Incorrect APT repository URL for 9.x

[Str0mfresser]

Type of issue

Inaccurate

What documentation page is affected

https://www.elastic.co/docs/reference/beats/filebeat/setup-repositories

What happened?

The instructions to add the Elastic 9.x APT repository are incorrect in the filebeat docs resulting in a HTTP 404 error when trying to fetch repository data via apt update:

Err: https://artifacts.elastic.co/packages/9.0/apt stable Release
  404  Not Found [IP: 34.120.127.130 443]
Error: The repository 'https://artifacts.elastic.co/packages/9.0/apt stable Release' does not have a Release file.

The version part in the URL should be 9.x instead of 9.0 like it used to be in previous versions (8.x, 7.x) and in similar docs like this: https://www.elastic.co/docs/deploy-manage/deploy/self-managed/install-elasticsearch-with-debian-package

The URL for OSS should be oss-9.x instead of oss-9.0.

For consistency, the sources files should also be named elastic-9.x.list instead of elastic-9.0.list.

Additional info

No response