Add beta documentation for Python and C++ library docs generation

[devin-ai-integration]

Summary

Adds a new documentation page (generate-library-docs.mdx) describing how to generate library documentation for Python and C++ projects using Fern. The page is:

• Marked as beta via availability: beta frontmatter and a warning callout
• Hidden from navigation (hidden: true in docs.yml) under API References > Generation
• Accessible only via direct URL at /learn/docs/api-references/generate-library-docs

The page covers configuration in docs.yml using the libraries key, with ParamField property reference, language-specific examples (Python and C++), multi-library setup, CLI commands to generate and preview docs, and guidance on writing effective source comments (Google-style docstrings for Python, Doxygen for C++). Uses plant-themed examples consistent with other docs pages.

Updates since last revision

• Simplified ParamField paths: Changed from verbose libraries.<name>.lang to just lang, input.git, etc.
• Added Doxyfile link: config.doxyfile description now links to the Doxygen configuration docs.
• Added "Generate your library docs" section: Documents the CLI commands to run after configuration (fern docs dev for local preview, fern generate --docs to publish).

Review & Testing Checklist for Human

• Verify docs.yml libraries schema is accurate: The config was written based on a screenshot of the schema. Confirm that input.git, input.subpath, output.path, lang, and config.doxyfile match the actual implementation. Pay attention to field names and nesting.
• Confirm CLI commands are correct for this feature: The page recommends fern docs dev (preview) and fern generate --docs (publish). Since this is a beta feature, verify these are the correct commands and that library docs generation is triggered through the standard docs pipeline.
• Confirm git is the only supported input type: The page states only git input is supported. Verify no other input types (e.g., local path) are available.
• Confirm config.doxyfile behavior: Page states the Doxyfile is read from disk and sent as raw content to the backend. Verify this is correct and C++-only.
• Preview the rendered page: Run fern docs dev and visit the page directly to verify it renders correctly with all components (ParamField, Tabs, code blocks, table).

Notes

• Vale linting passes with zero warnings on all revisions.
• The page was not tested locally with fern docs dev — rendering should be verified manually.
• CI checks (vale, check-assignee, run) all passed on every commit.

Requested by: Fern Support
Link to Devin Session

[devin-ai-integration]

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[fern-api]

Requested by: ryan stephen
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[github-actions]

🌿 Preview your docs: https://fern-preview-2d4243b6-71a9-4654-8a1a-ca9aac1aaad8.docs.buildwithfern.com/learn

Here are the markdown pages you've updated:

• learn/docs/api-references/generate-library-docs