Add parent/child resources section to Terraform comparison page

[joeduffy]

Fixes #11754.

Pulumi has an explicit parent/child resource model via the parent resource option that Terraform lacks. This is a genuine differentiator worth highlighting on the comparison page, as requested in the linked issue nearly five years ago.

Changes

• Feature table: Added a row for "Parent and Child Resources" in the feature comparison table, linking to the new section.
• New section: Added a "Parent and Child Resources" section after "Modular Resource Components" explaining:
  • How Pulumi's parent option establishes explicit parent/child relationships with lifecycle and option inheritance
  • How this is most commonly used with Component Resources
  • How Terraform modules differ — they are a static code-organization construct with no runtime parent/child linkage
  • Why this is a meaningful structural advantage for Pulumi users

The section follows the existing page style and links to the parent option docs for further reading.

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🧠 This PR was created by minime on behalf of @joeduffy.

[claude]

Docs Review — PR #17963

Scope: content/docs/iac/comparisons/terraform/_index.md (11 additions, 0 deletions)

Overall this is a clean, well-structured addition that fills a genuine gap in the comparison page. The content is accurate, follows the existing page patterns, and both internal links resolve correctly. A few minor items to consider:

Issues

1. Paragraph length (lines 256-257): The third paragraph (starting with "Terraform has no direct equivalent") is 4 sentences long and quite dense. The style guide recommends 3 sentences or fewer per paragraph. Consider splitting after the second sentence ("...rather than a runtime relationship.") to improve readability.

2. Promotional language (line 258): The phrase "meaningful structural advantage" is a value judgment. The rest of the section already demonstrates the advantage clearly through the feature comparison. The concluding paragraph could let the facts speak for themselves rather than editorializing. Consider softening to something like "Pulumi's parent/child resource model lets you reason about your infrastructure hierarchically..." without the explicit "meaningful structural advantage" framing.

3. Terraform state accuracy (line 256): The statement that resources in a Terraform module "exist as peers in the state file" is slightly imprecise. Terraform does namespace resources under their module path in state (e.g., module.foo.aws_instance.bar). The core point that there is no runtime parent/child linkage is correct. Consider rewording to: "the resources it contains are namespaced under the module path in state but without any explicit runtime parent/child linkage."

Style note (pre-existing, not introduced by this PR)

The H3 headings on this page use Title Case (e.g., "Custom Resource Providers," "Modular Resource Components"), which is inconsistent with the style guide rule that H2+ should use sentence case. The new heading "Parent and Child Resources" matches the existing page convention, so this is fine for consistency. Just noting it as a pre-existing deviation.

Verified

• Links: /docs/iac/concepts/components/ and /docs/iac/concepts/resources/options/parent/ both resolve to valid content files.
• Table row: Follows the existing pattern and placement is logical (after "Modular Resource Components," before "Execution Modes").
• Anchor: {#parent-child} is correctly referenced in the table link.
• No spelling/grammar errors detected.
• No missing aliases: no files were moved or renamed.
• No code examples to validate.

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Want me to make any fixes or do a deeper review? Mention me (@claude) in a comment.

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