Improve test readability

[akaIDIOT]

Fixes #126

Is there more we could and/or should improve? :)

[github-actions]

Comparing median (lower is better) metric of benchmarks between this PR's target (562ed1c) and the HEAD of this PR (29ff177):

	3.10	3.11	3.12	3.13	3.14	3.15	PyPy 3.10	PyPy 3.11
test_benchmark_get	-7%	+0%	-2%	+6%	+5%	+2%	-4%	-1%
test_benchmark_get_dotted	+1%	+1%	-2%	+6%	-2%	+2%	+2%	-3%
test_benchmark_getattr	-3%	-1%	-1%	+1%	-3%	+3%	+1%	+3%
test_benchmark_getitem	-6%	-1%	-1%	-1%	+5%	+2%	-3%	+1%
test_benchmark_getitem_dotted	+1%	-0%	-0%	+5%	+1%	+2%	-2%	-2%
test_benchmark_init_full_overlap	-2%	+1%	-2%	+5%	+7%	+1%	+1%	-1%
test_benchmark_init_no_overlap	-1%	-0%	-2%	+4%	+8%	+0%	+1%	-0%
test_benchmark_init_partial_overlap	-1%	-0%	-1%	+4%	+7%	+2%	-1%	+0%
test_benchmark_match_mapping	-3%	-1%	-1%	+2%	+2%	+1%	-2%	-2%
test_benchmark_reference_chain	+1%	+1%	+1%	+5%	-1%	+0%	-5%	+2%
test_benchmark_splat_args	+5%	+2%	+1%	+3%	-0%	+1%	-1%	-0%
test_benchmark_spread_kwargs	-1%	+2%	-0%	+5%	+2%	+3%	-4%	+6%

(This comment will be updated on subsequent pushes)