✨ Add macOS Help Book Integration

[suhang12332]

Description

Add native macOS Help Book integration to CodeEdit.
Currently, CodeEdit does not provide built-in documentation or Help Viewer integration.
Adding a Help Book (.help bundle) would allow users to access offline help content via the system Help Viewer, just like Apple's own apps.

Alternatives Considered

No response

Additional Context

Modern macOS apps like Xcode and Finder still use Help Books for user documentation.
It also supports localization and indexing (hiutil) for search.

Would be great to integrate this in a future release.

Screenshots

like this

[wjk]

If we are going to be considering adding a macOS Help Book to CodeEdit, there is an excellent example of how to make one in this repository under the CotEditor/Resources/CotEditor.help directory tree. Licensed under MIT.

Tip: There is a poorly-documented JavaScript function you can call that enables the Table of Contents button at the top of the macOS Sequoia Help Viewer window. You can find an example of its use here. Unfortunately, there is no (publicly known) way to use the table-of-contents sidebar in Help Viewer like with first-party apps. However, this technique does make it possible to link to a separate table-of-contents page, which is what is done in the linked code.