wc: use memchr crate for line counting

[xtqqczze]

No description provided.

[codspeed-hq]

Merging this PR will degrade performance by 42.87%

❌ 4 regressed benchmarks
✅ 305 untouched benchmarks
⏩ 46 skipped benchmarks¹

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

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	wc_lines_extreme_line_lengths[(100000, 200)]	1.6 ms	2.5 ms	-35.35%
❌	Simulation	wc_lines_large_line_count[500000]	2.8 ms	4.6 ms	-39.75%
❌	Simulation	wc_lines_variable_length[(50, 500)]	3.3 ms	5.6 ms	-40.27%
❌	Simulation	wc_bytes_lines_synthetic[2000]	120.1 ms	210.2 ms	-42.87%

---

_{Comparing xtqqczze:wc-memchr (4f29d53) with main (6130076)²}

Footnotes

1. 46 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on main (c146e8a) during the generation of this report, so 6130076 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[xtqqczze]

❌ Simulation wc_lines_large_line_count[500000] 2.8 ms 4.6 ms -39.67%
❌ Simulation wc_lines_extreme_line_lengths[(100000, 200)] 1.6 ms 2.5 ms -35.02%
❌ Simulation wc_bytes_lines_synthetic[2000] 120.1 ms 210.2 ms -42.87%
❌ Simulation wc_lines_variable_length[(50, 500)] 3.3 ms 5.6 ms -40.2%

All regressions, but maybe we can use bytecount crate instead of memchr elsewhere: #11872