Add descriptive error causes for reduce values errors #35

Performance Gate Passed

⚡ 1 improved benchmark
✅ 357 untouched benchmarks

	Benchmark	`BASE`	`HEAD`	Efficiency
⚡	`test_individual_cases[copium-cpython:91610:repeating_atomic]`	29.4 µs	22.7 µs	+29.8%

_{Comparing descriptive-reduce-error-causes (62d5c6e) with main (4bcdb4f)¹}

No successful run was found on main (475641d) during the generation of this report, so 4bcdb4f was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩