Implement AccessibilityHelp plugin for CKEditor5

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.

According to the IS, this needs tests. I didn't see any in the MR.

It looks like the config for the install profile(s) is also still needed.

The IS says:

editor users on NEW sites using Standard install profile: new button will be displayed in CKEditor 5 editor

Is that meant to include Demo Umami?

We want it enabled by default in both Basic HTML and Full HTML formats, correct?

Regarding the position of the button within the toolbar, my thought is to place it in the very first position because it provides info on using the other features through the keyboard and won't be hidden by wrapping. Attaching a screenshot.

Not currently working on this.