Refactor module init

[liamcmitchell]

Simplify html.js by moving all init into modules.

• run preview & hint first, they remove DOM, reducing work for other modules
• register swup:page:view callbacks from within modules
• move isEmbedded, isPreview and isHint into globals
• run module init from within modules
• adjust descriptionElementFromHash to also move comment nodes - preserving tabset comments
• inline many things in preview
• fix scroll caused by preview loading (on chrome/edge at least)
• fix quick switch link after swup nav (init wasn't called after nav)
• inline many things in sidebar version select
• move swup init into own module, it doesn't need to know about other modules now
• inline many things in hint-page

One thing I noticed when refactoring the init logic:

  if (isPreview && isEmbedded) {
    initPreview()
  } if (isHint && isEmbedded) {
    initHintsPage()
  } else {
  //  init swup, versions, keyboard shortcuts, qs, sidebar...

Notice that the second if is not an else if even though it's formatted like one. I assume that it was intended to be an else if and have refactored it that way.

By shuffling the module init and preventing a lot of unnecessary work, previews load almost 2x faster for me locally.

Before

After

-0.4kb JS

[github-actions]

📦 Docs artifacts are ready: https://github.com/elixir-lang/ex_doc/actions/runs/12694733371/artifacts/2408484853

[josevalim]

💚 💙 💜 💛 ❤️