[docs] [issue15554] correct and clarify str.splitlines() documentation

R. David Murray added the comment: Ah, I read too quickly before. But that expression "when a delimiter string *sep* is given" is hard to wrap ones head around in this context. I think the problem really is that 'split' has such radically different behavior when given an argument as opposed to when it isn't. I consider that a design flaw in split, and always have. So, I suppose we can't do any better here because of that. Please move the keeplines discussion back up into the initial paragraph, and then I think we'll be good to go. ---------- _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue15554> _______________________________________