Check more keys that just Tab to determine if in keyboard mode

[a11yup-old]

I am using this polyfill on a project with a couple of modal dialogs that can be triggered from different parts of the app. Whenever I close such a dialog via the Enter or Escape key focus is reset to the original place manually via .focus().

Unfortunately the .focus-ring class does not seem to be added, because only the Tab key is considered when setting the hadKeyboardEvent.

Would it make sense to add more keys like Enter, Escape and Space and Arrows?
I already tried this in my project and it seems to be fine.

I can create a PR for this.

[a11yup-old]

Just realised that there is a discussion in #54 already and #57 seems to address this. Didn't get that via their titles. Sorry about that. I am closing this.