message: fix(core/scope): use correct `this` in window unload listener
diff: @@ -83,6 +83,8 @@ export class Scope {
  }
  }
  + onWindowUnload = (event: BeforeUnloadEvent) => this.removeDocument(event.target as Document)
  +
  init (window: Window) {
  return initScope(this, window)
  }
  @@ -121,10 +123,6 @@ export class Scope {
  this.signals.fire('remove-document', { doc, window, scope: this, options })
  }
  - onWindowUnload (event: Event) {
  - this.removeDocument(event.target as Document)
  - }
  -
  getDocIndex (doc: Document) {
  for (let i = 0; i < this.documents.length; i++) {
  if (this.documents[i].doc === doc) {
  