Description:
------------
When creating a DatePeriod object using the "recurrences" constructor, it internally changes the counter by increasing it by 1.

As the test script illustrates the expectation would be to have the given count of iterations, but it actually contains one more.

The documentation at https://www.php.net/manual/en/class.dateperiod.php misses the details. My guess is some relation to the "include start date" option.


Test script:
---------------
<?php

$start = new DateTime('2018-12-31 00:00:00');
$interval = new DateInterval('P1M');
$recurrences = 5;

$period = new DatePeriod($start, $interval, $recurrences);
$dates = iterator_to_array($period);

assert($recurrences === $period->recurrences, 'The recurrences should match.');
assert($recurrences === count($dates), 'The iterator count should match the recurrences.');

var_dump(array_map(function(DateTime $date) { 
    return $date->format('Y-m-d'); 
}, iterator_to_array($period)));


Expected result:
----------------
My expectation would be to have 5 dates even when including the start date.

Actual result:
--------------
The actual result are 6 dates within the iterator.