Provide new AccessibilityHelp toolbar item in CKEditor 5 >=41.2

Thanks for creating this new issue! 🙏😄 That's super helpful and deeply appreciated! All I did was expand the issue metadata a bit more, and specifically call out that we want to change the default config in Standard/Demo Umami.

CKEditor 5 41.2.0 is now in core 👍

Interesting.. I hadn't heard of AccessibilityHelp before this:
https://ckeditor.com/docs/ckeditor5/latest/api/module_ui_editorui_access...

Documentation for authors is definitely important:
https://accessibilitycluster.com/main-results/documentation

But this seems to be about help for authors who need to learn the keystrokes that are needed to use CKEditor.

Keep in mind that there are inherent problems with Keyboard Shortcuts https://webaim.org/techniques/keyboard/accesskey

#4: Yep, noted. CKEditor 4 had something equivalent to this. In that sense, this is unfortunately simply catching up to the past.

This is already on the Essentials plugin, so just need to register the toolbar.