[DOC] PPL docs formatting for documentation-website

[kylehounslow]

Description

This PR contains the required PPL docs formatting fixes from vale linting, style guide, etc. for merging to main docs website: opensearch-project/documentation-website#11688.

Note

This PR will be work-in-progress as feedback is provided from docs writers in docs website PR

Summary of Changes

• Update all PPL docs with formatting fixes required to pass linting/review on documentation-website
• Update export_to_docs_website.py:
  • Auto-convert codeblock tables to markdown tables
  • Support single directory export
• Add README with SOP for docs exporter script

Related Issues

• PR to documentation-website: Export PPL Command docs from SQL plugin repo documentation-website#11688

Check List

• New functionality includes testing.
• New functionality has been documented.
• New functionality has javadoc added.
• New functionality has a user manual doc added.
• New PPL command checklist all confirmed.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff or -s.
• Public documentation issue/PR created.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[coderabbitai]

Important

Review skipped

Draft detected.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}