navigateRegions doesn't work from the editable blocks

[afercia]

navigateRegions is a keyboard-friendly feature that allows to navigate through the main Gutenberg areas with a keyboard shortcut. Pressing Ctrl + backtick focus is moved and cycles through the top toolbar, the editing area, and the sidebar. Shift + Ctrl + backtick cycles in the opposite direction.

Inspired by a similar feature in Slack, it has been brilliantly implemented and it's a great feature for keyboard users.

Unfortunately, seems to work only when focus is not inside an editable block, which kinda defects its purpose. At any moment, users should be able to use Ctrl + backtick to jump through the editor main sections, evne (an especially) when they're typing in an editable block.

To reproduce:

• using the keyboard, navigate to a non-editable block e.g. an image block
• press Ctrl + backtick and observe focus cycles through the 3 main editor sections
• tab into a paragraph, in the text area
• press Ctrl + backtick
• nothing happens

Note: honestly I'm not sure if navigateRegions has ever worked from editable blocks, but it's of fundamental importance to make it work from anywhere.

[afercia]

As far as I see, all that's needed here is to use bindGlobal for the Mousetrap shortcuts. PR incoming.