Remove :-khtml-drag pseudo-class alias

[nt1m]

157eda4

Remove `:-khtml-drag` pseudo-class alias
https://bugs.webkit.org/show_bug.cgi?id=267805
rdar://121303391

Reviewed by Anne van Kesteren.

Chrome has unshipped this for a while, let's give it a try. Firefox has never shipped this.

A quick Github search for `:-khtml-drag` shows a small number of hits: https://github.com/search?q=%3A-khtml-drag&;type=code

- Styling for dragging elements will change for the few sites that were using this.
- None of the hits are using `:-khtml-drag` in a selector list, which means this change wouldn't accidentally un-apply declarations for a different selector

* LayoutTests/imported/w3c/web-platform-tests/css/selectors/parsing/invalid-pseudos-expected.txt:
* LayoutTests/imported/w3c/web-platform-tests/css/selectors/parsing/invalid-pseudos.html:
* Source/WebCore/css/CSSPseudoSelectors.json:
* Source/WebCore/css/process-css-pseudo-selectors.py:
(InputValidator.validate_fields.is_known_prefix):

Canonical link: https://commits.webkit.org/273261@main

7879ccc

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 gtk
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash 7879ccc)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 gtk
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-commit-queue]

Committed 273261@main (157eda4): https://commits.webkit.org/273261@main

Reviewed commits have been landed. Closing PR #23012 and removing active labels.