CONTRIBUTING.md: discourage nitpicking #336200

Evaluator Performance Report

stat	before	after	Δ	Δ%
cpuTime	725.33	729.02	↗ 3.69	0.51%
envs-bytes	23,547,467,536	23,547,467,536	0
envs-elements	1,249,193,610	1,249,193,610	0
envs-number	847,119,916	847,119,916	0
gc-heapSize	69,898,051,584	69,881,278,464	↘ 16,773,120	-0.02%
gc-totalBytes	145,598,223,056	145,598,211,840	↘ 11,216	-0.00%
list-bytes	3,408,474,576	3,408,474,576	0
list-concats	89,516,196	89,516,196	0
list-elements	426,059,322	426,059,322	0
nrAvoided	981,223,172	981,223,172	0
nrFunctionCalls	777,446,638	777,446,638	0
nrLookups	407,614,207	407,614,207	0
nrOpUpdateValuesCopied	2,136,246,642	2,136,246,642	0
nrOpUpdates	98,148,127	98,148,127	0
nrPrimOpCalls	407,004,767	407,004,767	0
nrThunks	1,236,547,157	1,236,547,157	0
sets-bytes	48,405,031,264	48,405,031,264	0
sets-elements	2,842,605,997	2,842,605,997	0
sets-number	182,708,457	182,708,457	0
sizes-Attr	16	16	0
sizes-Bindings	16	16	0
sizes-Env	16	16	0
sizes-Value	24	24	0
symbols-bytes	3,144,237	3,144,237	0
symbols-number	184,287	184,287	0
values-bytes	37,873,511,904	37,873,511,904	0
values-number	1,578,062,996	1,578,062,996	0