Use Chain in traverseDirectly helpers

[valencik]

TLDR: Using Chain in traverseDirectly helpers is better than using Vector.

The data

Below are comparison tables from JMH runs.
All runs were done with the following:
bench/jmh:run -i 10 -wi 10 -f 2 -t 1 cats.bench.TraverseBench
And with the jvmopts: -Xms2G -Xmx12G

The "worst diff" column is the worst case comparison, if the new result was at the bottom of it's error bound, and the old result was at the top.
The "within" column is basically the best case comparison, if this value is positive than we are within error bounds or better.

Comparing this (which uses Chain) to the latest from PR 4498 (which uses Vector):

	this	error	PR 4498	error	worst diff	within
filterList	5683.922	79.338	5715.626	29.321	-140.363	76.955
filterVector	5573.414	72.463	5546.558	19.276	-64.883	118.595
mapList	5806.501	54.822	5767.038	34.619	-49.978	128.904
mapVector	6172.395	34.507	6173.065	40.277	-75.454	74.114
traverseChain	1383.903	18.172	1123.427	4.987	237.317	283.635
traverseChainError	2404.853	12.512	2127.662	13.144	251.535	302.847
traverseFilterChain	1390.162	2.67	1180.463	5.585	201.444	217.954
traverseFilterList	1208.214	15.235	1206.215	9.615	-22.851	26.849
traverseFilterVector	1193.495	11.759	1244.894	25.955	-89.113	-13.685
traverseList	1137.685	10.687	1069.802	13.869	43.327	92.439
traverseListError	2511.207	20.612	2167.488	21.981	301.126	386.312
traverseVector	1147.222	4.087	1152.973	25.078	-34.916	23.414
traverseVectorError	2542.108	10.112	2207.517	33.643	290.836	378.346
traverse_Chain	7685.159	158.094	7912.984	107.098	-493.017	37.367
traverse_List	9030.47	46.202	8934.534	46.916	2.818	189.054
traverse_Vector	8454.338	200.978	9092.209	36.689	-875.538	-400.204

Compairing this to cats main:

	this	error	main	error	worst diff	within
filterList	5683.922	79.338	5710.935	65.052	-171.403	117.377
filterVector	5573.414	72.463	5586.684	53.06	-138.793	112.253
mapList	5806.501	54.822	5794.559	31.269	-74.149	98.033
mapVector	6172.395	34.507	6156.259	29.844	-48.215	80.487
traverseChain	1383.903	18.172	1092.33	7.171	266.23	316.916
traverseChainError	2404.853	12.512	2713.055	41.359	-362.073	-254.331
traverseFilterChain	1390.162	2.67	982.057	6.179	399.256	416.954
traverseFilterList	1208.214	15.235	873.508	11.078	308.393	361.019
traverseFilterVector	1193.495	11.759	986.796	41.753	153.187	260.211
traverseList	1137.685	10.687	918.397	39.014	169.587	268.989
traverseListError	2511.207	20.612	2781.32	15.372	-306.097	-234.129
traverseVector	1147.222	4.087	997.688	4.798	140.649	158.419
traverseVectorError	2542.108	10.112	3081.201	31.311	-580.516	-497.67
traverse_Chain	7685.159	158.094	939.052	20.897	6567.116	6925.098
traverse_List	9030.47	46.202	808.78	8.011	8167.477	8275.903
traverse_Vector	8454.338	200.978	1111.32	9.188	7132.852	7553.184

[TimWSpence]

Thank you! I must have the same commit (possibly multiple times) in this branch's history 😆