fix: avoid BigInt literal in closeTo for runtime compat

[bheemreddy-samsara]

Summary

• Avoid emitting a BigInt literal in Assertion.closeTo, which causes Hermes (React Native) to fail bundle
  evaluation with No identifiers allowed directly after numeric literal.
• Use regular number math for abs so the code path stays compatible with engines lacking BigInt literal parsing.

Context

• RN 0.79.x, Hermes on Android.
• Chai 5.3.3.
• Hermes rejects the 0n literal during bundle load; app crashes before tests run.

Change

• lib/chai/core/assertions.js: change const abs = (x) => (x < 0n ? -x : x); to const abs = (x < 0 ? -x : x);
  and document the rationale.

Testing

• Verified on a React Native app with Hermes: harness tests now load and pass; the prior syntax error is gone.

[bheemreddy-samsara]

@snewcomer can i get a review on this ?

[bheemreddy-samsara]

@43081j Quick question on when will this be released ?

[43081j]

ill aim to release it in the next couple of days 👍

[bheemreddy-samsara]

@43081j do you have plan for the release before the new year ?

[43081j]

should be released in 6.2.2 👍

let me know if all is well

[bheemreddy-samsara]

@43081j thanks a ton :-) Happy Holidays and Merry Christmas