[energidataservice] Update JS example (openhab#16963)

Signed-off-by: Jimmy Tanagra <[email protected]>

Author: jimtng

bundles/org.openhab.binding.energidataservice/README.md

@@ -739,7 +739,7 @@ logInfo("Spot price two hours from now", price.toString)
 
 ```javascript
 var hourStart = time.toZDT().plusHours(2).truncatedTo(time.ChronoUnit.HOURS);
-var price = items.SpotPrice.history.historicState(hourStart).quantityState;
+var price = items.SpotPrice.persistence.persistedState(hourStart).quantityState;
 console.log("Spot price two hours from now: " + price);
 ```