Add PyO3 closure Sync fix commit reference

[cookesan]

Adds PyO3 closure Sync fix commit reference to GHSA-chgr-c6px-7xpp.

Audit refresh, July 8, 2026:

• Confirmed the live PR is open, ready for review, merge-clean, and the visible advisory check is green.
• Rechecked the merge-base diff: exactly one advisory JSON file changes (advisories/github-reviewed/2026/06/GHSA-chgr-c6px-7xpp/GHSA-chgr-c6px-7xpp.json), JSON parses, git diff --check passes, and the exact-head worktree is clean.
• Revalidated the added public references in the diff; all resolve through their source site or registry.

[cookesan]

Rechecked this reference-only PR while keeping the open Advisory Database queue current.

• The patch only adds the PyO3 closure Sync fix commit reference; it does not change affected ranges, package metadata, or severity.
• The commit resolves to 9cc78627df2e1268efd2e7973619301ae53c4834.
• The commit subject matches the advisory context: require PyCFunction::new_closure closures to be Sync (#6096).

No other advisory fields are changed.