extensions/html-language-features/server/src/modes/selectionRanges.ts/getSelectionRanges
export async function getSelectionRanges(languageModes: LanguageModes, document: TextDocument, positions: Position[]) {
	const htmlMode = languageModes.getMode('html');
	return Promise.all(positions.map(async position => {
		const htmlRange = await htmlMode!.getSelectionRange!(document, position);
		const mode = languageModes.getModeAtPosition(document, position);
		if (mode && mode.getSelectionRange) {
			let range = await mode.getSelectionRange(document, position);
			let top = range;
			while (top.parent && insideRangeButNotSame(htmlRange.range, top.parent.range)) {
				top = top.parent;
			}
			top.parent = htmlRange;
			return range;
		}
		return htmlRange || SelectionRange.create(Range.create(position, position));
	}));
}