chore(divan_compat): remove consts from unsupported features in README

[GuillaumeLagrange]

@not-matthias FYI

[codspeed-hq]

CodSpeed Instrumentation Performance Report

Merging #87 will not alter performance

_{Comparing remove-const-from-not-supported (17a5e27) with main (d722816)}

Summary

✅ 163 untouched benchmarks

[codspeed-hq]

CodSpeed Walltime Performance Report

Merging #87 will degrade performances by 52.21%

_{Comparing remove-const-from-not-supported (17a5e27) with main (d722816)}

Summary

⚡ 9 improvements
❌ 8 regressions
✅ 92 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
⚡	init_array[1000]	4 µs	2 µs	+97.02%
❌	generate_combinations[5]	3.2 µs	3.3 µs	-4%
⚡	generate_parentheses[3]	2.4 µs	2.3 µs	+3.11%
⚡	generate_parentheses[4]	7.3 µs	6.9 µs	+5.57%
⚡	generate_parentheses[5]	23.8 µs	21.9 µs	+8.89%
⚡	generate_parentheses[6]	72.6 µs	68.9 µs	+5.37%
❌	hamiltonian_cycle[4]	4.5 µs	4.6 µs	-3.13%
⚡	hamiltonian_cycle[7]	6.6 µs	6.4 µs	+3.75%
❌	permutations[3]	2.8 µs	2.9 µs	-3.27%
⚡	permutations[5]	14.6 µs	14.1 µs	+3.14%
❌	permutations[6]	66.8 µs	73.2 µs	-8.68%
⚡	permutations[7]	795.9 µs	766.2 µs	+3.88%
⚡	rat_in_maze[6]	5.6 µs	2.9 µs	+91.86%
❌	rat_in_maze[8]	3.7 µs	3.9 µs	-4.61%
❌	generate_gray_code[1]	2.1 µs	4.3 µs	-52.21%
❌	generate_gray_code[2]	3.8 µs	3.9 µs	-4.27%
❌	generate_gray_code[5]	3.7 µs	3.9 µs	-3.74%