[release] Add doc tests for important KubeRay docs

[kevin85421]

Search before asking

• I had searched in the issues and found no similar feature requirement.

Description

Based on ray-project/ray#50988

We can try to cover Step 1 in v1.4.0.

Step 1: Convert these 5 docs into doc tests.

• https://docs.ray.io/en/latest/cluster/kubernetes/getting-started/raycluster-quick-start.html
• https://docs.ray.io/en/latest/cluster/kubernetes/getting-started/rayjob-quick-start.html
• https://docs.ray.io/en/latest/cluster/kubernetes/getting-started/rayservice-quick-start.html
• https://docs.ray.io/en/latest/cluster/kubernetes/user-guides/configuring-autoscaling.html#kuberay-autoscaling
• https://docs.ray.io/en/latest/cluster/kubernetes/user-guides/kuberay-gcs-ft.html#kuberay-gcs-ft

Step 2: Convert CPU-only examples into doc tests.

• https://docs.ray.io/en/latest/cluster/kubernetes/examples.html

Step 3: Others

Use case

No response

Related issues

No response

Are you willing to submit a PR?

• Yes I am willing to submit a PR!