Add -w flag to butcher for water mobs

beb784e0ffe1d8a8cf678912dbd6207e96afcfc8

Co-Authored-By: Lewis B <17665267+lewisjb@users.noreply.github.com>

worldedit-sponge/src/main/java/com/sk89q/worldedit/sponge/SpongeEntityProperties.java

@@ -149,4 +149,9 @@ public class SpongeEntityProperties implements EntityProperties {
     public boolean isPasteable() {
         return !(entity instanceof Player || entity instanceof ComplexLivingPart);
     }
+
+    @Override
+    public boolean isWaterCreature() {
+        return false;  // TODO api8
+    }
 }