feat: Additional test to enforce documentation comment conventions

[bdferris-v2]

This PR adds an additional unit-test to enforce our documentation comment conventions, per https://github.com/MobilityData/gtfs-validator/blob/master/docs/NEW_RULES.md#2-document-the-new-rule. This is a cleanup task for #1324.

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• Run the unit tests with gradle test to make sure you didn't break anything
• Format the title like "feat: [new feature short description]". Title must follow the Conventional Commit Specification(https://www.conventionalcommits.org/en/v1.0.0/).
• Linked all relevant issues
• Include screenshot(s) showing how this pull request works and fixes the issue(s)

[github-actions]

✅ Rule acceptance tests passed.
New Errors: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
Dropped Errors: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
New Warnings: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
Dropped Warnings: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
0 out of 1428 sources (~0 %) are corrupted.
Commit: 61b9a14
Download the full acceptance test report here (report will disappear after 90 days).
✅ Rule acceptance tests passed.

[github-actions]

✅ Rule acceptance tests passed.
New Errors: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
Dropped Errors: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
New Warnings: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
Dropped Warnings: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
0 out of 1428 sources (~0 %) are corrupted.
Commit: 583492d
Download the full acceptance test report here (report will disappear after 90 days).
✅ Rule acceptance tests passed.

[github-actions]

✅ Rule acceptance tests passed.
New Errors: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
Dropped Errors: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
New Warnings: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
Dropped Warnings: 0 out of 1428 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
0 out of 1428 sources (~0 %) are corrupted.
Commit: 98a4e0c
Download the full acceptance test report here (report will disappear after 90 days).
✅ Rule acceptance tests passed.