Document new key builtin_default_value of the array returned by ini_get_all() in PHP >= 8.6.0

[sebastianbergmann]

This updates the documentation for ini_get_all() after php/php-src#22134.

[jordikroon]

LGTM. Just a few style guide nits. Also meant to reduce the chances of a merge conflict later om.

[jordikroon]

This should probably wait until PHP 8.6 actually drops.

[jordikroon]

@lacatoire as long as those inner para's do not change. There is no need to suggest to migrate to simpara. It will only put the bar up unnecessarily for the contributors. Though it's up to Sebastian if he wishes to include them. It's just extra maintenance work.

[sebastianbergmann]

This should probably wait until PHP 8.6 actually drops.

This updates the documentation of ini_get_all() for PHP 8.6, yes. I do not know the policy for the documentation, sorry, so I do not know whether this can be merged now or whether it needs to wait until PHP 8.6 has been released.

[jordikroon]

@sebastianbergmann there isn't really a policy, but best to wait for alpha 1 before merging.
That said any MR targeting 8.6 is very welcome and will save us time preparing. So we are very happy with it (If only more would do this ^^).

[jordikroon]

In preparation for 8.6, this has been rebased and style changes have been fixed.
No further action required, and ready to be merged once RC1 or Hard freeze is place.