[issue #2221] simplified configuration for @Singular-generated plural form nullchecks.

test/transform/resource/after-ecj/SuperBuilderBasic.java

@@ -21,7 +21,9 @@ public class SuperBuilderBasic {
       }
       public @java.lang.SuppressWarnings("all") B items(final java.util.Collection<? extends String> items) {
         if ((items == null))
-            throw new java.lang.NullPointerException("items cannot be null");
+            {
+              throw new java.lang.NullPointerException("items cannot be null");
+            }
         if ((this.items == null))
             this.items = new java.util.ArrayList<String>();
         this.items.addAll(items);