transform method
Implementation
@override
String transform(Node node, DocumentMarkdownEncoder? encoder) {
assert(node.type == 'code');
final delta = node.delta;
final language = node.attributes['language'] ?? '';
if (delta == null) {
throw Exception('Delta is null');
}
final markdown = DeltaMarkdownEncoder().convert(delta);
final result = '```$language\n$markdown\n```';
final suffix = node.next == null ? '' : '\n';
return '$result$suffix';
}