GH-47100: [Docs] Correct the Statistics schema specification

[thisisnic]

Rationale for this change

Docs were incorrect apparently

What changes are included in this PR?

Update them

Are these changes tested?

Nope

Are there any user-facing changes?

No

• GitHub Issue: [Specification][Statistics] Correct the Statistics schema specification. #47100

[github-actions]

⚠️ GitHub issue #47100 has been automatically assigned in GitHub to PR creator.

[Copilot]

Pull request overview

This PR corrects the Arrow Statistics schema specification documentation to remove references to “table” as a statistics target, aligning the spec text with the intended scope (record batches / arrays) described in issue #47100.

Changes:

• Clarified that column = null indicates statistics for the whole record batch or array (not a table).
• Updated multiple sentences to state statistics can apply to a column, record batch, or array (removing “table”).
• Updated ARROW:row_count:{exact,approximate} descriptions to refer to record batch or array only.

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[kou]

+1

Thanks!

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 3 benchmarking runs that have been run so far on merge-commit 3c9cb0c.

There were no benchmark performance regressions. 🎉

The full Conbench report has more details. It also includes information about 44 possible false positives for unstable benchmarks that are known to sometimes produce them.