extensions/emmet/src/util.ts/isOffsetInsideOpenOrCloseTag
export function isOffsetInsideOpenOrCloseTag(node: FlatNode, offset: number): boolean {
	const htmlNode = node as HtmlFlatNode;
	if ((htmlNode.open && offset > htmlNode.open.start && offset < htmlNode.open.end)
		|| (htmlNode.close && offset > htmlNode.close.start && offset < htmlNode.close.end)) {
		return true;
	}

	return false;
}