`some <html/>` compiles to (not (hs-falsy? (hs-query-first "html"))), which
called document.querySelector('html'). The mock's querySelector searched
only inside _body, so the html element wasn't found. Adjusted the mock to
return _html for the 'html' selector (and walk documentElement too).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>