Add line lineSeparator for generate file & format code

[lwj1994]

@SheetLocalization(
  //...
  lineSeparator: '\n',
)
class _Strings {}

Add lineSeparator for generateFile，because default is CRLF('\r\n').

And fix:

LF can't be parse. so  `lines.first.subList(1,l)`  will RangeError:

RangeError (index): Invalid value: Only valid value is 0: 1

[lwj1994]

@rinlv hi ，Please consider my pr