Keep strings before incomplete escape sequences in partial mode

[dittos]

Fixes #207

[codecov]

Codecov Report

Attention: Patch coverage is 87.50000% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
crates/jiter/src/string_decoder.rs	87.50%	0 Missing and 2 partials ⚠️

📢 Thoughts on this report? Let us know!

[codspeed-hq]

CodSpeed Performance Report

Merging #208 will improve performances by 41.26%

_{Comparing dittos:partial-escape (ba4012a) with main (e6b28c2)}

Summary

⚡ 19 improvements
✅ 51 untouched benchmarks

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
⚡	big_jiter_iter	36.9 ms	27.4 ms	+34.53%
⚡	floats_array_jiter_iter	184.7 µs	157.8 µs	+17.08%
⚡	medium_response_jiter_skip	16.9 µs	15.3 µs	+10.6%
⚡	pass2_jiter_iter	6.7 µs	4.8 µs	+39.19%
⚡	pass2_jiter_skip	2.2 µs	1.9 µs	+15.63%
⚡	sentence_jiter_skip	2.2 µs	1.7 µs	+24.66%
⚡	sentence_serde_value	8.9 µs	8 µs	+11.61%
⚡	string_array_jiter_iter	7.9 µs	5.7 µs	+38.53%
⚡	true_array_jiter_iter	4.5 µs	3.7 µs	+23.98%
⚡	true_object_jiter_iter	22 µs	19.8 µs	+11.1%
⚡	true_object_jiter_skip	13.1 µs	11.5 µs	+13.28%
⚡	unicode_jiter_iter	8.5 µs	7.7 µs	+10.24%
⚡	unicode_jiter_skip	2.3 µs	1.9 µs	+22.59%
⚡	unicode_serde_value	9.6 µs	8.6 µs	+11.06%
⚡	x100_jiter_iter	1.3 µs	1.1 µs	+23.74%
⚡	x100_jiter_skip	1,241.9 ns	879.2 ns	+41.26%
⚡	x100_jiter_value	1.7 µs	1.4 µs	+17.86%
⚡	x100_serde_iter	2.9 µs	2.3 µs	+27.78%
⚡	python_parse_massive_ints_array	1.3 ms	1.2 ms	+11.66%

[davidhewitt]

LGTM, thanks!