v17.1.0

• Added parseURLWithValidationErrors(), which records and returns validation errors per the standard's parsing algorithm, often performing additional checks on the input.
• Added isValidURLString(), which checks an input string against the standard's valid URL string predicate.
• Fixed userinfo parsing for astral code points (@spokodev, #333). This was a rare instance of whatwg-url failing to match the specification.

Notably, the new validation code allowed us to make significant progress on whatwg/url#704, and as far as we can tell at this point, the two types of validation agree.