[Sync EN] POSIX: add changelog entries for PHP 8.5 changes

PR: `https://github.com/php/doc-en/pull/5534` (2026-05-13)

**Файлы RU для обновления**
- `reference/posix/functions/posix-fpathconf.xml`
- `reference/posix/functions/posix-isatty.xml`
- `reference/posix/functions/posix-kill.xml`
- `reference/posix/functions/posix-setpgid.xml`
- `reference/posix/functions/posix-setrlimit.xml`
- `reference/posix/functions/posix-ttyname.xml`

