Improve hiding content docs to better distinguish hidden vs noindex

[devin-ai-integration]

Summary

Restructures the Hiding content page to better distinguish hidden: true from noindex: true, based on user feedback that the current page was misleading.

Key changes:

• Intro: Replaced single-paragraph description with a bullet list clearly defining each setting's behavior
• Hiding a page: Clarified that page-level hidden: true automatically excludes from search — no need to also set noindex in frontmatter
• New section "Excluding a page from search only": Promoted the noindex-only use case from a buried <Info> callout to its own section with a standalone code example
• Hiding a section or version: Added explicit contrast with page-level behavior ("Unlike page-level hidden...")
• Cross-references updated: SEO metadata page and hidden page example updated to match new messaging

Review & Testing Checklist for Human

• Verify that page-level hidden: true does in fact auto-set noindex. This is the central claim of the rewrite and came from internal Slack — if the product behavior differs, the docs would be wrong.
• The hidden page example (hiding-content-example.mdx) still has noindex: true in its frontmatter (line 3). Consider whether to remove it since the docs now say it's redundant, or leave it as-is.
• Preview the rendered page to confirm the new structure (intro bullets, two distinct sections for hidden vs noindex) reads well and the code examples are clear.

Notes

• The metadata.mdx file had pre-existing Vale errors unrelated to this PR (pixel units, Twitter heading casing); those were left as-is.
• The llms-txt.mdx cross-reference was already accurate and didn't need changes.

Link to Devin session: https://app.devin.ai/sessions/edf7c4c922c44979bacea6e1fcadd67a

[devin-ai-integration]

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[fern-api]

Requested by: jon
Slack thread: View conversation

[github-actions]

🌿 Preview your docs: https://fern-preview-devin-1775519214-improve-hiding-content-docs.docs.buildwithfern.com/learn

Here are the markdown pages you've updated:

• learn/docs/customization/hidden-page
• learn/docs/customization/hiding-content
• learn/docs/seo/setting-seo-metadata