docs(feature_flags): snippets split, improved, and lint

[leandrodamascena]

Issue number: #1373

Summary

Changes snippet fictitious names to real code snippet filenames for easier discovery and collaboration to improve/correct document snippets.

Some examples have also been refactored so that the codes are complete and there are no lint/pre-commit hooks issues.

User experience

BEFORE

AFTER

Checklist

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• Meet tenets criteria
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• PR title follows conventional commit semantics

Is this a breaking change?

RFC issue number:

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

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[github-actions]

⚠️Large PR detected⚠️

Please consider breaking into smaller PRs to avoid significant review delays. Ignore if this PR has naturally grown to this size after reviews.

[github-actions]

⚠️Large PR detected⚠️

Please consider breaking into smaller PRs to avoid significant review delays. Ignore if this PR has naturally grown to this size after reviews.

[rubenfonseca]

Will review this later today

[rubenfonseca]

I pushed two small fixes and left two comments to think about. Great great work Leandro!

[rubenfonseca]

Loved the changes explaining the get vs get_raw. Thank you for this awesome work Leo!