[Sync EN] Add PHP 8.4.0 changelog entries for PGSQL and PDO pages

PR: `https://github.com/php/doc-en/pull/5364` (2026-07-23)

**Файлы RU для обновления**
- `reference/pdo/pdo/getattribute.xml`
- `reference/pgsql/functions/pg-fetch-result.xml`
- `reference/pgsql/functions/pg-field-is-null.xml`
- `reference/pgsql/functions/pg-field-prtlen.xml`

