Improve javadoc for some addons (#15701)

Signed-off-by: Holger Friedrich <mail@holger-friedrich.de>

bundles/org.openhab.io.homekit/src/main/java/org/openhab/io/homekit/internal/accessories/AbstractHomekitAccessoryImpl.java

@@ -84,6 +84,8 @@ public abstract class AbstractHomekitAccessoryImpl implements HomekitAccessory {
     /**
      * Gives an accessory an opportunity to populate additional characteristics after all optional
      * charactericteristics have been added.
+     * 
+     * @throws HomekitException
      */
     public void init() throws HomekitException {
     }
@@ -333,6 +335,9 @@ public abstract class AbstractHomekitAccessoryImpl implements HomekitAccessory {
      * of the caller to add characteristics when the primary service is created.
      *
      * @param characteristic
+     * @throws NoSuchMethodException
+     * @throws IllegalAccessException
+     * @throws InvocationTargetException
      */
     @NonNullByDefault
     public void addCharacteristic(Characteristic characteristic)