parse method
Implementation
@override
Node parse(BlockParser parser) {
var pos = parser._pos + parser.offset;
var childLines = parseChildLines(parser);
// Recursively parse the contents of the blockquote.
var itemParser = parser.document.getBlockParser(childLines)
..offset = pos
.._inList = parser._inList;
var children = itemParser.parseLines();
return Element('blockquote', children);
}