docs(samples): include metadata file, add exclusions for samples to handwritten libraries

[gcf-owl-bot]

• Regenerate this pull request now.

PiperOrigin-RevId: 429395631

Source-Link: googleapis/googleapis@84594b3

Source-Link: https://github.com/googleapis/googleapis-gen/commit/ed74f970fd82914874e6b27b04763cfa66bafe9b
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiZWQ3NGY5NzBmZDgyOTE0ODc0ZTZiMjdiMDQ3NjNjZmE2NmJhZmU5YiJ9

feat: add symbols field, and auto-format comments
PiperOrigin-RevId: 428800506

Source-Link: googleapis/googleapis@ea20380

Source-Link: https://github.com/googleapis/googleapis-gen/commit/8b9ece508c132516f4bf79e462f08253acc85935
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiOGI5ZWNlNTA4YzEzMjUxNmY0YmY3OWU0NjJmMDgyNTNhY2M4NTkzNSJ9

feat: add symbols field, and auto-format comments
PiperOrigin-RevId: 428799963

Source-Link: googleapis/googleapis@8b6181f

Source-Link: https://github.com/googleapis/googleapis-gen/commit/2c320a956160ee86cb8d7923e37a1a3a451d1042
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiMmMzMjBhOTU2MTYwZWU4NmNiOGQ3OTIzZTM3YTFhM2E0NTFkMTA0MiJ9

[snippet-bot]

No region tags are edited in this PR.

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment

[gcf-merge-on-green]

Merge-on-green attempted to merge your PR for 6 hours, but it was not mergeable because either one of your required status checks failed, one of your required reviews was not approved, or there is a do not merge label. Learn more about your required status checks here: https://help.github.com/en/github/administering-a-repository/enabling-required-status-checks. You can remove and reapply the label to re-run the bot.