toSequenceParser method
Converts the parser in this iterable to a sequence of parsers.
For example, the parser [letter(), digit(), letter()].toSequenceParser()
accepts a letter followed by a digit and another letter. The parse result
of the input string 'a1b' is the list <String>['a', '1', 'b'].
Implementation
@useResult
Parser<List<R>> toSequenceParser() => SequenceParser<R>(this);