docs(s3): document region_name connection parameter

[Beandon13]

Summary

• Adds the missing region_name parameter to the Amazon S3 integration page (Required/Optional connection parameters list and the CREATE DATABASE example).
• The parameter is already documented in docs/integrations/data-integrations/all-data-integrations.mdx and honored by the handler, but is absent from the standalone Amazon S3 page.
• Without it, users hitting endpoints that require an explicit region (or who don't want the implicit GetBucketLocation round trip) have to discover it from issue trackers.

Refs: #12286

Testing

• Doc-only change. Verified the rendered MDX renders alongside the existing parameter list. No code paths touched.

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[entelligence-ai-pr-reviews]

EntelligenceAI PR Summary

This PR updates the Amazon S3 integration documentation to document the optional region_name connection parameter.

• Added region_name to the CREATE DATABASE code snippet in amazon-s3.mdx
• Included a parameter description covering its purpose and default fallback behavior when omitted
• Noted potential performance and compatibility implications of not specifying the region

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Confidence Score: 5/5 - Safe to Merge

Safe to merge — this PR makes a straightforward documentation-only change to amazon-s3.mdx, adding the optional region_name connection parameter to the CREATE DATABASE code snippet along with a clear description of its purpose, default fallback behavior, and performance/compatibility implications. No logic, runtime, or security concerns are present since this is purely additive documentation. The change accurately reflects real AWS SDK behavior where omitting region_name causes the SDK to fall back to environment/config-based resolution, which is a useful clarification for users.

Key Findings:

• The change is confined entirely to documentation in amazon-s3.mdx with no code path, configuration logic, or runtime behavior modified.
• The description of region_name correctly conveys its optional nature and the fallback behavior when omitted, which aligns with how boto3/AWS SDKs handle region resolution.
• No review comments were generated and heuristic analysis found zero issues across all severity levels, making this a clean documentation-only addition.

Files requiring special attention

• amazon-s3.mdx