SPIGOT-7383: Add EntityDamageEvent.DamageCause#KILL and EntityDamageEvent.DamageCause#WORLD_BORDER

By: Doc <nachito94@msn.com>

paper-api/src/main/java/org/bukkit/event/entity/EntityDamageEvent.java

@@ -8,6 +8,7 @@ import java.util.EnumMap;
 import java.util.Map;
 import java.util.Objects;
 import org.bukkit.Material;
+import org.bukkit.WorldBorder;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.Player;
 import org.bukkit.event.Cancellable;
@@ -260,6 +261,18 @@ public class EntityDamageEvent extends EntityEvent implements Cancellable {
      */
     public enum DamageCause {
 
+        /**
+         * Damage caused by /kill command
+         * <p>
+         * Damage: {@link Float#MAX_VALUE}
+         */
+        KILL,
+        /**
+         * Damage caused by the World Border
+         * <p>
+         * Damage: {@link WorldBorder#getDamageAmount()}
+         */
+        WORLD_BORDER,
         /**
          * Damage caused when an entity contacts a block such as a Cactus,
          * Dripstone (Stalagmite) or Berry Bush.
@@ -356,7 +369,7 @@ public class EntityDamageEvent extends EntityEvent implements Cancellable {
          * Damage caused by committing suicide.
          * <p>
          * <b>Note:</b> This is currently only used by plugins, default commands
-         * like /minecraft:kill use {@link #VOID} to damage players.
+         * like /minecraft:kill use {@link #KILL} to damage players.
          * <p>
          * Damage: variable
          */