[Sync EN] Add manual for grapheme_levenshtein function. (#5005)

[github-actions]

Commit: https://github.com/php/doc-en/commit/469efd89e78e8d003d7222550f7cdcf4a8f417b1
PR: https://github.com/php/doc-en/pull/5005

Nuevos archivos EN (aún no traducidos)

• reference/intl/grapheme/grapheme-levenshtein.xml