Improve VoiceOver support for the EPUBNavigatorViewController

[mickael-menu]

Added

Navigator

• The EPUB navigator automatically moves to the next resource when VoiceOver reaches the end of the current one.

Fixed

Navigator

• Fixed activating the scroll mode when VoiceOver is enabled in the EPUB navigator.

[ettore]

would it be possible to add some code documentation to explain the difference (conceptually) between EPUBSettings, EPUBPreferences, EPUBDefaults? they seem closely related. Or maybe it already exists and I am missing it?

[mickael-menu]

Could you take a look at this and tell me if that helps to understand it?
https://github.com/readium/architecture/blob/master/proposals/009-preferences-api.md#overview

There's also this, but maybe it's not clear enough:

swift-toolkit/Sources/Navigator/Preferences/Configurable.swift

Lines 19 to 24 in 4a9a4d9

	/// Submits a new set of `Preferences` to update the current `Settings`.
	///
	/// Note that the `Configurable` might not update its `settings` right away, or might even
	/// ignore some of the provided preferences. They are only used as hints to compute the new
	/// settings.
	func submitPreferences(_ preferences: Preferences)

Generally, you can ignore XSettings as an integrator. It will be used by the EPUBPreferencesEditor.

[ettore]

Could you take a look at this and tell me if that helps to understand it? https://github.com/readium/architecture/blob/master/proposals/009-preferences-api.md#overview

This is great! I didn't know it existed. IMO it would be great to have a link to this in the code where the related types (EPUBPreferences, EPUBSettings, EPUBDefaults) are defined. I can also contribute that if not clear.

There's also this, but maybe it's not clear enough:

This is useful too (although a bit buried) but not as foundational as the documentation you linked.

[mickael-menu]

Actually we have even better, there's a Swift-specific user guide for that here: https://github.com/readium/swift-toolkit/blob/main/Documentation/Guides/Navigator%20Preferences.md#configuring-the-navigator

That could be useful to link to this markdown. Ideally we could add something like this <doc:Guides/NavigatorPreferences> but I think we need to setup a DocC documentation catalog for this first.

[ettore]

I was even thinking we could just add that URL to the class doc, i.e. at line 12 of EPUBSettings (or equivalent in EPUBPreferences).

[mickael-menu]

Sure that could be enough until we add a real DocC catalog.