tokenize method
Continues highlighting that HighlightedDiff.of left unfinished, the
new file first, for at most budget. Returns isComplete.
Implementation
bool tokenize({Duration? budget}) {
final clock = Stopwatch()..start();
for (final side in _sides) {
if (side.isComplete) continue;
if (!side.tokenize(budget: _left(budget, clock))) break;
}
return isComplete;
}