[Sync EN] Clarify closing identifier indentation behaviour of Heredoc (#5763)

[github-actions]

Commit: https://github.com/php/doc-en/commit/0d964bcaac6618dd80b974eb6fcdf3c67ca07340
PR: https://github.com/php/doc-en/pull/5763

Archivos ES a actualizar

• language/types/string.xml