selectors crate test failed with 68aa48d7

[ycytt-rs]

change set 68aa48d7d041012e04e0c10071cd20822de0d655 would cause the test cases:

• parser::tests::test_parsing
• parser::tests::visitor

failed

thread 'parser::tests::visitor' panicked at 'called Result::unwrap()on anErr value: ParseError { kind: Custom(InvalidPseudoClassBeforeWebKitScrollbar), location: SourceLocation { line: 0, column: 7 } }', selectors/parser.rs:3433:35

The captioned changeset would cause parsing :not(:hover) ~ label faileed