Release v3.14.0

Fixed

• Ignore NUL after a less-than sign in HTML text and in CDATA at HTML/MathML integration points, while preserving foreign-text and RAWTEXT replacement rules.
• Preserve non-ASCII whitespace in class and attribute tokens, selector identifiers, HTML cleanup, and pretty output.
• Apply ASCII whitespace rules to CSS declarations, URL lists, encoding labels, and streamed doctypes.
• Reject malformed :nth-child() / :nth-of-type() formulas without accepting Unicode digits or Python integer syntax.
• Keep a <button> nested when an object, applet, marquee, table cell, caption or integration point separates it from an open <button>, instead of closing the outer one across that scope boundary.

Performance

• Share class and attribute token sets within selector queries and allocate attribute caches only when needed.