fix: Fix Renfe FIP issuer content (#741) (#807)

- Fix minor content issue on the Renfe FIP issuer page that caused
incorrect wording in English.
- Edit: `content/operator/renfe/index.en.md` (1 insertion, 1 deletion).

This PR aims to resolve issue #741 by correcting the English content on
the Renfe operator page.

Testing:
- Local repo changes committed on branch `fix/741`.

Please review and merge when ready. Closes #741.

Co-authored-by: Robert Schuster <77234379+therobrob@users.noreply.github.com>

Author: lenderom

content/operator/renfe/index.en.md

@@ -11,7 +11,7 @@ Renfe Operadora is the state-owned railroad company in [Spain](/country/spain "S
 
 ## Summary
 
-- FIP free tickets are accepted on commuter trains (mainly suburban trains), but not on trains requiring reservations.
+- FIP Coupons are accepted on commuter trains (mainly suburban trains), but not on trains requiring reservations.
 - For trains requiring reservations, tickets can be purchased at the FIP Global Fare (regardless of distance), including the reservation; FIP Coupons are not needed.
 - FIP is not accepted on Avlo trains.
 - For international AVEs between Madrid and Marseille as well as Lyon and Barcelona, the same FIP Global Fares apply as for domestic AVEs.