strong method
Strong emphasis (**bold** or __bold__).
Implementation
Parser<StrongNode> strong() => [
seq5(
position(),
string('**'),
ref0(strongAsteriskContent),
string('**'),
position(),
).map5(
(start, _, content, _, stop) =>
StrongNode(content, start: start, stop: stop),
),
seq5(
position(),
string('__'),
ref0(strongUnderscoreContent),
string('__'),
position(),
).map5(
(start, _, content, _, stop) =>
StrongNode(content, start: start, stop: stop),
),
].toChoiceParser();