fix(css_parser): accept more valid CSS identifiers

[Conaclos]

Summary

Fix #3627

CSS allows a wider rang e of characters for identifiers than JS:

ident-start code point
    A letter, a non-ASCII ident code point, or U+005F LOW LINE (_). 
ident code point
    An ident-start code point, a digit, or U+002D HYPHEN-MINUS (-).
non-ASCII ident code point
    A [code point](https://infra.spec.whatwg.org/#code-point) whose value is any of:
        U+00B7
        between U+00C0 and U+00D6
        between U+00D8 and U+00F6
        between U+00F8 and U+037D
        between U+037F and U+1FFF
        U+200C
        U+200D
        U+203F
        U+2040
        between U+2070 and U+218F
        between U+2C00 and U+2FEF
        between U+3001 and U+D7FF
        between U+F900 and U+FDCF
        between U+FDF0 and U+FFFD
        greater than or equal to U+10000

Why these character, specifically?

This matches the list of non-ASCII codepoints allowed to be used in HTML valid custom element names. It excludes a number of characters that appear as whitespace, or that can cause rendering or parsing issues in some tools, such as the direction override codepoints.

Note that this is a weaker set of restrictions than UAX 31 recommends for identifiers (used by languages such as JavaScript to restrict their identifier syntax), allowing things such as starting an identifier with a combining character. Consistency with HTML custom element names (and thus, the ability to write selectors for all custom elements without having to use escapes) was considered valuable, and the set of characters restricted by HTML covers the "high value" restrictions well.

Test Plan

I added a test.

[codspeed-hq]

CodSpeed Performance Report

Merging #3771 will degrade performances by 17.31%

_{Comparing conaclos/css-ident-parsing (1b9e8dd) with main (0b83351)}

Summary

⚡ 15 improvements
❌ 1 regressions
✅ 83 untouched benchmarks

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

Benchmarks breakdown

	Benchmark	main	conaclos/css-ident-parsing	Change
❌	css_formatter[semantic_2402227530816031580.css]	299.2 ms	361.9 ms	-17.31%
⚡	bootstrap_18416142857265205439.css[cached]	47.6 ms	42 ms	+13.16%
⚡	bootstrap_18416142857265205439.css[uncached]	51.2 ms	45.7 ms	+11.87%
⚡	bulma_15117074458139280020.css[cached]	45.2 ms	40.3 ms	+12.24%
⚡	bulma_15117074458139280020.css[uncached]	49.3 ms	44.3 ms	+11.5%
⚡	foundation_7285025277362245733.css[cached]	30.1 ms	27.2 ms	+10.52%
⚡	foundation_7285025277362245733.css[uncached]	32.7 ms	29.5 ms	+10.54%
⚡	full_5814491140539129161.css[cached]	503.7 ms	463.6 ms	+8.66%
⚡	full_5814491140539129161.css[uncached]	530 ms	485.7 ms	+9.12%
⚡	materialize_13055388268705992476.css[cached]	33.6 ms	30.1 ms	+11.54%
⚡	materialize_13055388268705992476.css[uncached]	36.5 ms	33.1 ms	+10.36%
⚡	pure_9395922602181450299.css[cached]	3.9 ms	3.5 ms	+12.35%
⚡	pure_9395922602181450299.css[uncached]	4.5 ms	4.1 ms	+9.3%
⚡	semantic_2402227530816031580.css[cached]	143.6 ms	128.3 ms	+11.91%
⚡	semantic_2402227530816031580.css[uncached]	153.3 ms	136.6 ms	+12.29%
⚡	tachyons_9066552643484828443.css[cached]	21.5 ms	20 ms	+7.57%