Derive the EN source file path from a translated file path. e.g. news/2026-04-09-committee-reports-de.html → news/2026-04-09-committee-reports-en.html
Derive the EN source file path from a translated file path. e.g. news/2026-04-09-committee-reports-de.html → news/2026-04-09-committee-reports-en.html