Upgrading react-i18next from 17.x to 18.x

Released together with i18next 27. The migration guide lists every change with what to do: https://react.i18next.com/latest/migrating-v17-to-v18

### Breaking changes

- requires i18next 27 (peer `>= 27.0.0`) and React 18 or later (peer `>= 18.0.0`). React 16 and 17 apps stay on react-i18next 17: on i18next 27, use react-i18next 17.1.13 or later (it brings the types of the `react` init options), or 18. `useSyncExternalStore` comes from React itself, so `use-sync-external-store` is no longer a dependency.
- `Trans` output no longer depends on `interpolation.escapeValue`: it always decodes HTML entities after parsing, as `IcuTrans` does, in text and in attribute values, both with `react.unescape` (attribute values used the built-in decoder before). With i18next's default `escapeValue: true`, a value `Tom & Jerry` rendered as `Tom & Jerry` and a date `17/12/2025` as `17/12/2025`; both now render as written, and so do entities in the translation itself (`&`, `<`, ` `, ...). Values still render as text, never as markup (since 17.1.10). The `shouldUnescape` prop and `react.transDefaultProps.shouldUnescape` are ignored and warn (`DEPRECATED_OPTION`, in development and with `debug: true`); remove them. Snapshot tests that contain entities inside `Trans` output need an update ([#1903](https://github.com/i18next/react-i18next/issues/1903), [#1893](https://github.com/i18next/react-i18next/issues/1893)).
- `Trans` and `IcuTrans` re-render on language change by themselves: they subscribe to the `react.bindI18n` (default `languageChanged`) and `react.bindI18nStore` events, like `useTranslation`. Before, they only updated when a parent re-rendered ([#1710](https://github.com/i18next/react-i18next/issues/1710)). They still neither load translations nor suspend; with a `t` prop, that `t` still decides the language. `TransWithoutContext` and `IcuTransWithoutContext` stay hook-free.
- the `react` options of an instance stay on that instance. `initReactI18next` copied them into module-wide defaults, so a second instance without `react` options inherited, for example, the first one's `useSuspense: false`. Set them on every instance, or call `setDefaults()` once.
- the `i18n` returned by `useTranslation` (and passed by `withTranslation` and `Translation`) forwards reads and writes to the instance. It was a copy taken when the language changed, so after `await i18n.changeLanguage('de')` the copy still said `en`, and properties set on it never reached the instance. It is still a new object whenever the language changes, for dependency arrays and the React Compiler. Because the old object now reads the current language too, a check like `prevProps.i18n.language !== this.props.i18n.language` (or the language of a `usePrevious(i18n)`) no longer sees a change: compare the objects (`prevProps.i18n !== this.props.i18n`) or keep the previous language yourself.
- `useSSR` and `withSSR` call i18next's `hydrate()` instead of writing `resourceStore.data`,

Between react-i18next 17.1.13 and 18.0.0, Vigia found 0 removed exports, 5 changed signatures and 0 removed or changed class or interface members.

1 exports or members are newly marked as deprecated in react-i18next 18.0.0.