Fix issue 27197: Remove window's copy of DOMContentLoaded; redirect to document's copy

[wbamberg]

Fixes #27197. Also fixes #19269.

This PR:

• deletes Window's version of DOMContentLoaded
• folds the info from Adding missing detail to DOMContentLoaded #19924 into Document's version
• redirects Window's version to Document's
• updated all the places Yari complained about links to Window's version

I think this is what we want here?

I also deleted the para about synchronous JS, as this seemed very out of date and AFAICT is solved these days by defer.

[github-actions]

Preview URLs (11 pages)

• /en-US/docs/Learn/Performance/HTML
• /en-US/docs/Learn/Performance/JavaScript
• /en-US/docs/Mozilla/Add-ons/WebExtensions/API/webNavigation/onDOMContentLoaded
• /en-US/docs/Mozilla/Add-ons/WebExtensions/API/webNavigation
• /en-US/docs/Mozilla/Add-ons/WebExtensions/Content_Security_Policy
• /en-US/docs/Web/API/Document/DOMContentLoaded_event
• /en-US/docs/Web/API/HTMLScriptElement
• /en-US/docs/Web/API/Window
• /en-US/docs/Web/Events
• /en-US/docs/Web/Performance/Navigation_and_resource_timings
• /en-US/docs/Web/Performance

Flaws (37)

Note! 5 documents with no flaws that don't need to be listed. 🎉

URL: /en-US/docs/Web/Events
Title: Event reference
Flaw count: 6

• broken_links:
  • Can't resolve /en-US/docs/Web/API/SVGElement/abort_event
  • Can't resolve /en-US/docs/Web/API/SVGElement/resize_event
  • Can't resolve /en-US/docs/Web/API/SVGElement/scroll_event
  • Can't resolve /en-US/docs/Web/API/SVGElement/unload_event
  • Can't resolve /en-US/docs/Web/API/Window.devicemotion_event
  • and 1 more flaws omitted

---

URL: /en-US/docs/Web/API/HTMLScriptElement
Title: HTMLScriptElement
Flaw count: 13

• macros:
  • /en-US/docs/Web/API/Element/error_event redirects to /en-US/docs/Web/API/HTMLElement/error_event
  • /en-US/docs/Web/API/HTMLScriptElement/type does not exist
  • /en-US/docs/Web/API/HTMLScriptElement/src does not exist
  • /en-US/docs/Web/API/HTMLScriptElement/event does not exist
  • /en-US/docs/Web/API/HTMLScriptElement/charset does not exist
  • and 8 more flaws omitted

---

URL: /en-US/docs/Web/API/Document/DOMContentLoaded_event
Title: Document: DOMContentLoaded event
Flaw count: 1

• macros:
  • /en-US/docs/Web/API/Window/DOMContentLoaded_event redirects to /en-US/docs/Web/API/Document/DOMContentLoaded_event

---

URL: /en-US/docs/Web/API/Window
Title: Window
Flaw count: 12

• macros:
  • /en-US/docs/Web/API/Window/setResizable does not exist
  • /en-US/docs/Web/API/Window/animationcancel_event redirects to /en-US/docs/Web/API/Element/animationcancel_event
  • /en-US/docs/Web/API/Window/animationend_event redirects to /en-US/docs/Web/API/Element/animationend_event
  • /en-US/docs/Web/API/Window/animationiteration_event redirects to /en-US/docs/Web/API/Element/animationiteration_event
  • /en-US/docs/Web/API/Window/animationstart_event redirects to /en-US/docs/Web/API/Element/animationstart_event
  • and 7 more flaws omitted

---

URL: /en-US/docs/Web/Performance
Title: Web performance
Flaw count: 4

• broken_links:
  • Can't resolve /en-US/docs/Learn/Performance/Mobile
  • Can't resolve /en-US/docs/Web/API/Performance_API/Using_the_Performance_API
  • Can't resolve /en-US/docs/Web/API/Performance_Timeline/Using_Performance_Timeline
  • Can't resolve /en-US/docs/Web/API/Performance_Timeline

---

URL: /en-US/docs/Web/Performance/Navigation_and_resource_timings
Title: Navigation and resource timings
Flaw count: 1

• broken_links:
  • Can't resolve /en-US/docs/Web/API/Window/DOMContentLoaded_event

[rebloor]

In context of the other changes, the changes to the web extension pages look OK.