[Sync EN] doc: clarify unary-vs-instanceof precedence and assignment binding inside prefix operators (#5627)

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Commit: https://github.com/php/doc-en/commit/80dfa568e602649eb13585bf59a7b6239eddaac3
PR: https://github.com/php/doc-en/pull/5627

Zu aktualisierende DE-Dateien

• language/operators/precedence.xml