Let's add interpolation support for <transform-list>, + and # custom properties.
Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/37565
Pull request: https://github.com/WebKit/WebKit/pull/7776
Committed 258039@main (384557c7e6f7): <https://commits.webkit.org/258039@main> Reviewed commits have been landed. Closing PR #7776 and removing active labels.
<rdar://problem/103477663>