fix(format/html): keep at most 1 empty line between elements

[dyc3]

Summary

Prettier preserves at most 1 empty line (2 newlines) between tags. This PR makes it so that Biome matches the newline preserving behavior of Prettier.

It feels a bit hacky, but it gets the job done. Since this was originally ported from the JsxChildList behavior, this code makes a bunch of assumptions about the parsing that are not true for the HTML parser. Planning to go through it eventually to clean it up and simplify it, which will be a lot easier to do when we have sufficient tests.

Caution

This PR is stacked on the following PRs. Do not merge it without merging the others and rebasing this branch. To review this PR, look at the last commit only.

• refactor(parser/html): refactor comments to be nodes in the tree #4056

fixes #3973

Test Plan

Added a few tests.

[github-actions]

Parser conformance results on

js/262

Test result	main count	This PR count	Difference
Total	48534	48534	0
Passed	47341	47341	0
Failed	1193	1193	0
Panics	0	0	0
Coverage	97.54%	97.54%	0.00%

jsx/babel

Test result	main count	This PR count	Difference
Total	40	40	0
Passed	37	37	0
Failed	3	3	0
Panics	0	0	0
Coverage	92.50%	92.50%	0.00%

symbols/microsoft

Test result	main count	This PR count	Difference
Total	6570	6570	0
Passed	2203	2203	0
Failed	4367	4367	0
Panics	0	0	0
Coverage	33.53%	33.53%	0.00%

ts/babel

Test result	main count	This PR count	Difference
Total	680	680	0
Passed	608	608	0
Failed	72	72	0
Panics	0	0	0
Coverage	89.41%	89.41%	0.00%

ts/microsoft

Test result	main count	This PR count	Difference
Total	18433	18433	0
Passed	14114	14114	0
Failed	4319	4319	0
Panics	0	0	0
Coverage	76.57%	76.57%	0.00%

[codspeed-hq]

CodSpeed Performance Report

Merging #4057 will improve performances by 7.13%

_{Comparing 09-23-fix_format_hml_keep_at_most_1_empty_line_between_elements (0941f0b) with main (ab0f96e)}

Summary

⚡ 1 improvements
✅ 106 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	09-23-fix_format_hml_keep_at_most_1_empty_line_between_elements	Change
⚡	react.production.min_3378072959512366797.js[cached]	2 ms	1.8 ms	+7.13%