Document Trino advanced properties and update extension sidebar/config docs

[mtoy-googly-moogly]

Summary

• Add documentation for Trino source, ssl, session, extraCredential, and extraHeaders connection properties, with an example and a note about json type behavior
• Update extension sidebar docs to reflect per-file connection resolution and the file icon affordance
• Rewrite config search docs to explain the walk-up-to-root lookup behavior and subdirectory overrides

Test plan

• Verify the Trino properties table renders correctly
• Confirm the JSON example block renders properly
• Review extension sidebar and config search sections for accuracy against current extension behavior

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