[Sync-EN] Document the ZipArchive deferred write behavior

[lacatoire]

Syncs reference/zip/ziparchive/close.xml and reference/zip/ziparchive/open.xml with php/doc-en#5274.

• ZipArchive::close(): adds the note that adding, removing and renaming entries happens in memory and reaches the disk only when close() is called, so file system errors such as permission denied or a missing directory surface at close time rather than when the modification methods are called.
• ZipArchive::open(): adds the matching note for ZipArchive::CREATE, where the file is not written until close() is called, so file system errors are reported there and not by open().

EN-Revision bumped to 5cb356334f35b9ae452e3af47d2d9f0b1cd16b63 on both files.

Fixes: #1661