Remove optgroup element removal and moving steps

[josepharhar]

These steps are obsolete now that option elements look through their entire ancestor chain and run the same algorithm when being inserted, removed, or moved.

Mentioned in #11730

• At least two implementers are interested (and none opposed):
  • Chrome
  • WebKit
• Tests are written and can be reviewed and commented upon at:
  • Probably any test which has an optgroup with options in it is affected by running the selectedness setting algorithm when the optgroup is inserted.
• Implementation bugs are filed:
  • Chromium: Already implemented
  • Gecko: https://bugzilla.mozilla.org/show_bug.cgi?id=1933591
  • WebKit: https://bugs.webkit.org/show_bug.cgi?id=283732
• Corresponding HTML AAM & ARIA in HTML issues & PRs: not needed
• MDN issue is filed: not needed
• The top of this comment includes a clear commit message to use.

(See WHATWG Working Mode: Changes for more details.)

---

/form-elements.html ( diff )