useHotKeys: Allow unbinding hotkeys within a scope if provided

[tkoenig]

This partially fixes #177 , as it at least now allows to unbind the shortcuts within a scope if one has been provided.

Example

import { Controller } from "@hotwired/stimulus";
import { useHotkeys, useThrottle } from "stimulus-use";

export default class extends Controller {
  static values = { key: String, scope: { type: String, default: "app" } };
  static throttles = ["fire"];
  connect() {
    useThrottle(this, { wait: 2000 });
    hotkeys = {};
    hotkeys[this.keyValue] = { handler: this.fire, options: { scope: this.scopeValue } };
    useHotkeys(this, { hotkeys: hotkeys });
  }

  fire() {
    this.element.click();
  }
}

<button data-action="dialog#close" data-controller="hotkey" data-hotkey-scope-value="preview" data-hotkey-key-value="Esc" type="button">
  Close
</button>


<button data-action="selection#empty" data-controller="hotkey" data-hotkey-scope-value="selection" data-hotkey-key-value="Esc" type="button">
  Empty selection
</button>

So when Closing the dialog, the Esc key gets unbound correctly, while the Empty selection hotkey will still work.

[tkoenig]

Actually it was easier using hotkeys.js directly and since stimulus will get support for keyboard events (hotwired/stimulus#442) there is probably no more need for that.