[Sync EN] XML Entities by example (#5634)

[github-actions]

Commit: https://github.com/php/doc-en/commit/bd3f9a8c0412e902be8fc1c1ff9acac906826aa6
PR: https://github.com/php/doc-en/pull/5634

Nuevos archivos EN (aún no traducidos)

• docbookcs.xml