test(parse): add assertion for v6 inline reference behavior (#4619)

* test(parse): add assertion for v6 inline reference behavior

Verify that inline references are captured in the references array,
documenting the behavioral change from v5 where they remained in body.

* test(parse): document complete v6 inline reference behavior

Add assertions to verify that:
- Both reference instances are captured (2 total)
- Body content with references moves to footer
- Each reference object includes the raw source line

This comprehensively documents the behavioral change from v5
(references stayed in body) to v6 (references move to footer).

* test(parse): split inline reference test into two focused tests

Separate concerns for better clarity:
- Test 1: Inline reference parsing (verifies v6 moves body refs to footer)
- Test 2: Comment line filtering (verifies commentChar option works)

This addresses co-maintainer feedback about the confusing mixed test.