[Sync EN] appendices: note the E_STRICT deprecation (8.4.0), mark T_PROPERTY_C available as of 8.4.0 (#5799)

Commit: `https://github.com/php/doc-en/commit/5a91c9a81ee5c2560a15f1fca84bc5a6148cca9a`
PR: `https://github.com/php/doc-en/pull/5799`

**Archivos ES a actualizar**
- `appendices/reserved.constants.core.xml`
- `appendices/tokens.xml`

