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

By: Doc <nachito94@msn.com>

paper-server/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java

@@ -1027,6 +1027,10 @@ public class CraftEventFactory {
             cause = DamageCause.DRYOUT;
         } else if (source.is(DamageTypes.FREEZE)) {
             cause = DamageCause.FREEZE;
+        } else if (source.is(DamageTypes.GENERIC_KILL)) {
+            cause = DamageCause.KILL;
+        } else if (source.is(DamageTypes.OUTSIDE_BORDER)) {
+            cause = DamageCause.WORLD_BORDER;
         } else {
             cause = DamageCause.CUSTOM;
         }