Consolidate BQ reservation resources to one section in docs

[modular-magician]

Closes #11619

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• Generated Terraform, and ran make test and make lint to ensure it passes unit and linter tests.
• Ensured that all new fields I added that can be set by a user appear in at least one example (for generated resources) or third_party test (for handwritten resources or update tests).
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Release Note Template for Downstream PRs (will be copied)

Consolidate BQ reservation resources to one section in docs

Derived from GoogleCloudPlatform/magic-modules#6675

[github-actions]

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