docs: pipeline: filters: kubernetes: document kube_namespace_file option

[eschabell]

Add the kube_namespace_file option to the configuration table. The filter reads the pod namespace from this configurable path instead of a hard-coded location.

Note this update due to code change without matching docs PR.

Summary by CodeRabbit

• Documentation
  • Added a new Kubernetes filter configuration option, kube_namespace_file, to the configuration table.
  • Documented its purpose (path to the pod namespace file) and default value.
  • Refreshed wording/formatting in the metadata cache and freshness section and adjusted an example heading for clearer presentation.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Configuration used: defaults

Review profile: CHILL

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Run ID: 2a83a338-2eea-490d-9806-e2b4fb21f56e

📥 Commits

Reviewing files that changed from the base of the PR and between 1d34093 and d92bbe1.

📒 Files selected for processing (1)

• pipeline/filters/kubernetes.md

🚧 Files skipped from review as they are similar to previous changes (1)

• pipeline/filters/kubernetes.md

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📝 Walkthrough

Walkthrough

This change updates the Kubernetes filter documentation with a new kube_namespace_file configuration entry and minor nearby text formatting changes.

Changes

Documentation update

Layer / File(s)	Summary
Add kube_namespace_file parameter row pipeline/filters/kubernetes.md	Adds the kube_namespace_file table row, re-renders the cache introduction text, and updates the StatefulSet Pod example heading formatting.

Estimated code review effort: 1 (Trivial) | ~2 minutes

Possibly related PRs

• fluent/fluent-bit-docs#2611: Modifies the same Kubernetes filter documentation area around metadata cache behavior.

Suggested labels: documentation

Suggested reviewers: None specified

Poem

A namespace path joins the page,
With tidy text and polished stage.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly states the Kubernetes filter docs change and the new kube_namespace_file option.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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• Create PR with unit tests

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[eschabell]

@patrick-stephens ready for review!

[patrick-stephens]

Do we know the original PR that added this btw?