docs: document searchable option for hidden navigation elements

[mintlify]

Summary

Documents the new searchable property on hidden tabs, groups, anchors, and dropdowns. When set alongside hidden: true, descendant pages stay in site search, the sitemap, llms.txt, AI assistant context, and search engine indexing while remaining hidden from the sidebar.

Changes

• Added a "Keep hidden pages discoverable with searchable" section to organize/hidden-pages.mdx with a configuration example and a list of behaviors enabled by the flag.
• Added a searchable ResponseField next to the existing hidden field for tabs, anchors, and dropdowns in organize/settings-structure.mdx.
• Mirrored both updates across the es, fr, and zh translations.

Context

Backs the discovery-surface changes in mintlify/server#5291, which route the search index, sitemap, llms.txt, AI assistant content, and SEO metadata through a searchable-aware hidden lookup so opt-in pages no longer receive noindex while still being excluded from the rendered navigation.

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Note

Low Risk
Low risk documentation-only change that clarifies behavior of hidden navigation items and introduces no runtime/code-path modifications.

Overview
Adds documentation for a new searchable: true flag that can be combined with hidden: true on navigation elements (tabs/groups/anchors/dropdowns) to keep descendant pages included in site search, sitemap, llms.txt, AI assistant context, and SEO indexing while still hiding them from the sidebar.

Updates the docs.json schema docs (settings-structure.mdx) to include the searchable field next to hidden for tabs, anchors, and dropdowns, and mirrors these docs updates across es, fr, and zh locales.

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