[fix] whitespace html entities lost in component slot

[xxkl1]

closes: #8359

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Tests

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The reason is due to the following code

svelte/src/compiler/compile/nodes/InlineComponent.ts

Lines 170 to 172 in d42ca04

	function not_whitespace_text(node) {
	return !(node.type === 'Text' && regex_only_whitespaces.test(node.data));
	}

svelte/src/compiler/utils/patterns.ts

Line 7 in d42ca04

export const regex_only_whitespaces = /^\s+$/;

  is non-breaking space characte, /\s/ match it and judging that it should not be retained.

  in <span>&nbsp;</span> use [ \t\r\n] so it will not be delete.

<Component>
	<span>&nbsp;</span>
</Component>

svelte/src/compiler/compile/render_dom/wrappers/Fragment.ts

Lines 102 to 104 in d42ca04

	if (should_trim && !child.keep_space()) {
	data = trim_end(data);
	if (!data) continue;

svelte/src/compiler/utils/trim.ts

Lines 7 to 9 in d42ca04

	export function trim_end(str: string) {
	return str.replace(regex_ends_with_whitespaces, '');
	}

svelte/src/compiler/utils/patterns.ts

Line 6 in d42ca04

export const regex_ends_with_whitespaces = /[ \t\r\n]*$/;

/\s/ is looks equal with /[ \u00A0\u2009\u200C\u200D\u3000\t\n\r\f]/, \u00A0\u2009\u200C\u200D\u3000 is unicode code of \  \&thinsp \‌ \‍  .

I think we can use [ \t\n\r\f] equals with [\u0020\t\n\r\f] to solve this problem, \u0020 is standard space character we need skip.

The test error of html space entities will be hided by /\s/ in normalizeHtml. The reason is html space entities be replace to '', so /\s/ need to replaced by [ \t\n\r\f] and save html space entities in test too.

svelte/test/helpers.ts

Lines 143 to 155 in d42ca04

	export function normalizeHtml(window, html, preserveComments = false) {
	try {
	const node = window.document.createElement('div');
	node.innerHTML = html
	.replace(/(<!--.*?-->)/g, preserveComments ? '$1' : '')
	.replace(/>[\s\r\n]+</g, '><')
	.trim();
	cleanChildren(node);
	return node.innerHTML.replace(/<\/?noscript\/?>/g, '');
	} catch (err) {
	throw new Error(`Failed to normalize HTML:\n${html}`);
	}
	}

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[dummdidumm]

Thank you!