New Issue: [Library Stabilization] Should 'bigint.gcdext()' return a tuple of values?

17707, "lydia-duncan", "[Library Stabilization] Should 'bigint.gcdext()' return a tuple of values?", "2021-05-12T21:47:55Z"

Seems like we could return s and t as a tuple of values like bigint.get_d_2exp() does (though that arguably does fall under the performance question in #17699 )