`skipTrivia` skipped `// line comments` but not `/* block comments */`, so one
written between two page or component members failed with a bare "Unexpected
character '/'". Block comments inside a braced body already worked, which made
the failure look arbitrary: the same comment parsed or did not depending on
whether it happened to sit inside a block.
`startsWithBlockComment` now skips only whitespace and line comments, so
`props {}` keeps refusing block comments with its own explained error rather
than silently swallowing one and dropping the declaration after it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>