Merge ServiceWorkerState into ServiceWorker.state

[teoli2003]

This fixes #5617.

ServiceWorkerState is an enum only used in ServiceWorker.state. From a developer perspective it is a JS String with a fixed state of values.

This, it is better to describe the values directly in ServiceWorker.state, and to completely hide ServiceWorkerState from the developer (like mixins, it is an implementation detail).

This PR does this.

[github-actions]

Preview URLs

• https://pr5660.content.dev.mdn.mozit.cloud/en-US/docs/Web/API/Service_Worker_API
• https://pr5660.content.dev.mdn.mozit.cloud/en-US/docs/Web/API/ServiceWorker/state

Flaws

Note! 1 document with no flaws that don't need to be listed. 🎉

URL: /en-US/docs/Web/API/Service_Worker_API
Title: Service Worker API
on GitHub
Flaw count: 2

• macros:
  • /en-US/docs/Web/API/PeriodicSyncRegistration does not exist
  • /en-US/docs/Web/API/SyncRegistration does not exist

External URLs

URL: /en-US/docs/Web/API/Service_Worker_API
Title: Service Worker API
on GitHub

• https://alistapart.com/article/application-cache-is-a-douchebag (1 time) (Note! This may be a new URL 👀)

---

URL: /en-US/docs/Web/API/ServiceWorker/state
Title: ServiceWorker.state
on GitHub

No new external URLs