Replace $ sign for all strings and not only for the ones that don't have a new line.

[issdn]

Moved the replaceAll('\$', '\\\$') statement out of the if (!s.contains('\n')) so that $s in strings with a \n are also escaped.
Theoretically also raw strings could be used for these paragraphs which would save bit of performance I guess.

        if (!s.contains('\n')) {
          return 'r' + quote + s.replaceAll(quote, "\\$quote").replaceAll('\$', '\\\$') + quote;
        }
        final q3 = quote * 3;
        return 'r' + q3 + s.replaceAll(q3, '\\$quote' * 3) + q3;

Tested on the license of syncfusion_flutter_charts package.