Add Javadoc to public interface

Signed-off-by: Jacob Laursen <jacob-github@vindvejr.dk>

bundles/org.openhab.binding.energidataservice/src/main/java/org/openhab/binding/energidataservice/internal/provider/listener/Co2EmissionListener.java

@@ -27,7 +27,22 @@
  */
 @NonNullByDefault
 public interface Co2EmissionListener extends SubscriptionListener {
+ /**
+ * Current realtime emission or prognosis has been updated.
+ *
+ * @param type The type (either {@link Co2EmissionSubscription.Type#Realtime} or
+ * {@link Co2EmissionSubscription.Type#Prognosis})
+ * @param emission Emission in g/kWh
+ */
  void onCurrentEmission(Co2EmissionSubscription.Type type, BigDecimal emission);
 
+ /**
+ * Realtime emissions or prognosis have changed.
+ * Can be used to update time series.
+ *
+ * @param type The type (either {@link Co2EmissionSubscription.Type#Realtime} or
+ * {@link Co2EmissionSubscription.Type#Prognosis})
+ * @param emissions Emissions in g/kWh
+ */
  void onEmissions(Co2EmissionSubscription.Type type, Map<Instant, BigDecimal> emissions);
 }