Fix type for index in ZipArchive::replaceFile

[kingkero]

see php/doc-en#1563

In all of the ZipArchive methods, the index is always described as int (see https://www.php.net/manual/en/class.ziparchive.php). Only for the replaceFile it is documented as string. However, actually passing a string will trigger (in PHP 8.1.5)

Fatal error: Uncaught TypeError: ZipArchive::replaceFile(): Argument php/doc-en#2 ($index) must be of type int, string given

TypeError: ZipArchive::replaceFile(): Argument php/doc-en#2 ($index) must be of type int, string given

[remicollet]

Squashed and merged in 8.0 as 389d113