comments in parasplit out of date

[xtqqczze]

• "peek ahead" seems pointless
• "need to explicitly force fl out of scope before we can call self.lines.next()" is incorrect because fl is in fact in scope when we call next(), it seems a refactoring in 01c32a5 put it in scope.

cc: @tertsdiepraam

Originally posted by @xtqqczze in #10754 (comment)