src/vs/editor/common/languages/supports/richEditBrackets.ts/BracketsUtils/_findPrevBracketInText
class BracketsUtils:	private static _findPrevBracketInText(reversedBracketRegex: RegExp, lineNumber: number, reversedText: string, offset: number): Range | null {
		const m = reversedText.match(reversedBracketRegex);

		if (!m) {
			return null;
		}

		const matchOffset = reversedText.length - (m.index || 0);
		const matchLength = m[0].length;
		const absoluteMatchOffset = offset + matchOffset;

		return new Range(lineNumber, absoluteMatchOffset - matchLength + 1, lineNumber, absoluteMatchOffset + 1);
	}