[SPARK-51883][DOCS][PYTHON] Python Data Source user guide for filter pushdown

[wengh]

What changes were proposed in this pull request?

Update python_data_source.rst to add filter pushdown docs.

Why are the changes needed?

Feature was added but documentation was still missing.

Does this PR introduce any user-facing change?

No

How was this patch tested?

Verified locally

Was this patch authored or co-authored using generative AI tooling?

Yes. Initial draft was generated using AI then manually edited.

Generated-by: GitHub Copilot with Claude 3.7 Sonnet

[wengh]

@wengh this looks good! Could you also attach a screenshot for the updated user guide to the PR description? Thanks!

done 🤗

[xinrong-meng]

Would you rebase master changes? The CI test failure should have been fixed

[github-actions[bot]]

We're closing this PR because it hasn't been updated in a while. This isn't a judgement on the merit of the PR in any way. It's just a way of keeping the PR queue manageable. If you'd like to revive this PR, please reopen it and ask a committer to remove the Stale tag!