strikethrough method
GFM strikethrough (~~deleted~~).
Implementation
Parser<StrikethroughNode> strikethrough() =>
seq5(
position(),
string('~~'),
ref0(strikethroughContent),
string('~~'),
position(),
).map5(
(start, _, content, _, stop) =>
StrikethroughNode(content, start: start, stop: stop),
);