src/vs/editor/common/model/bracketPairsTextModelPart/bracketPairsTree/ast.ts/TextAstNode/computeMinIndentation
class TextAstNode:	public computeMinIndentation(offset: Length, textModel: ITextModel): number {
		const start = lengthToObj(offset);
		// Text ast nodes don't have partial indentation (ensured by the tokenizer).
		// Thus, if this text node does not start at column 0, the first line cannot have any indentation at all.
		const startLineNumber = (start.columnCount === 0 ? start.lineCount : start.lineCount + 1) + 1;
		const endLineNumber = lengthGetLineCount(lengthAdd(offset, this.length)) + 1;

		let result = Number.MAX_SAFE_INTEGER;

		for (let lineNumber = startLineNumber; lineNumber <= endLineNumber; lineNumber++) {
			const firstNonWsColumn = textModel.getLineFirstNonWhitespaceColumn(lineNumber);
			const lineContent = textModel.getLineContent(lineNumber);
			if (firstNonWsColumn === 0) {
				continue;
			}

			const visibleColumn = CursorColumns.visibleColumnFromColumn(lineContent, firstNonWsColumn, textModel.getOptions().tabSize)!;
			result = Math.min(result, visibleColumn);
		}

		return result;
	}