Handle new CommentKind variants to unblock cross-platform gem build

[Copilot]

The build started failing after upgrading oxc because rust/src/parse.rs no longer exhaustively matched CommentKind. New HtmlOpen/HtmlClose variants triggered E0004 during Rust compilation in the GitHub Actions packaging job.

• Parser compatibility update

  • Extend comment-kind mapping in collect_comments to handle newly introduced oxc variants.
  • Map HtmlOpen and HtmlClose to Ruby-facing "Line" comments to preserve existing comment typing semantics.

• Regression coverage

  • Add focused parser tests for HTML-style comments to ensure both open (<!--) and close (-->, script mode) forms are serialized as line comments.

kind: match comment.kind {
  CommentKind::Line => "Line",
  CommentKind::SingleLineBlock | CommentKind::MultiLineBlock => "Block",
  CommentKind::HtmlOpen | CommentKind::HtmlClose => "Line",
},