Extract an independently mergeable topic from wpt-misc-fix at
a70a96f9d1.
Register the child text content regression module without including later script test modules.
Include the XML document fixture route used by the CDATA regression so this branch does not depend on the separate XML input-stream changes.
Source commits:
- 7f587e1251
- ae3a3f1096
Validation:
- cargo fmt --all
- cargo clippy --workspace --all-targets --all-features -- -D warnings
- cargo nextest run --no-fail-fast
