[RFC]: add support for viewing API docs for C APIs

[kgryte]

Description

This RFC proposes to add support for viewing API docs for C APIs.

Currently, the side menu includes all packages. When writing native add-ons and C APIs, would be useful to limit the side menu to only those packages containing C APIs. Preferably, when limiting to C API packages, only the C API documentation would be present upon navigating to a package README.

Related Issues

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Questions

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Other

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Checklist

• [X] I have read and understood the Code of Conduct.
• [X] Searched for existing issues and pull requests.
• [X] The issue name begins with RFC:.