Utf8::wordwrap and strings with new lines

[matlouis]

Utf8::wordwrap doesn't work correctly when the input string contains new lines:

$str = "string\nwith\nnew\nlines";
echo \Patchwork\Utf8::wordwrap($str);

should output the string unchanged (like php's wordwrap), but it outputs:

string
stringwith
stringwithnew
stringwithnewlines