Add "Keyboard navigation" system preference

[TrevorBurnham]

This PR adds a page for the "Keyboard navigation" system preference, which allows users to use Tab and Shift+Tab to navigate in all system dialogs.

[yannbertrand]

Didn't know about that one, thanks for the discovery!

Could you add some example usages?

That article looks interesting as well.

[yannbertrand]

I believe those screenshots are not really useful, maybe this kind of screenshots can help:

https://help.apple.com/assets/6716DCA9E121372173069823/6716DCAAD224F0859301B7BA/en_US/d9186a08bd176803ec1e7d09c96ad2c6.png

I'm not even sure it can help understand what the command does. wdyt?

[TrevorBurnham]

I've updated the PR with screenshots to demonstrate a classic use case: Navigating a "Do you want to save?" dialog. See e.g. this popular Ask Different question: https://apple.stackexchange.com/questions/55292/how-do-i-negotiate-dialogue-boxes-using-the-keyboard-only

Let me know if there's anything I can do to make the functionality clearer. I'd be happy to add an annotation to the "enabled" screenshot, but I don't see any examples of that in the existing screenshots.

[yannbertrand]

Let me know if there's anything I can do to make the functionality clearer. I'd be happy to add an annotation to the "enabled" screenshot, but I don't see any examples of that in the existing screenshots.

Yea it's about limiting the screenshots. When updating to a new macOS version I try to recapture all existing screenshots but it can take a lot of time. That's why I like to add a "Set value from UI" section at the end of the page, especially if there is a direct link :)

[yannbertrand]

This is great! Thank you