`#no_nil` third time's the charm

src/llvm_backend_debug.cpp

@@ -439,7 +439,7 @@ gb_internal LLVMMetadataRef lb_debug_union(lbModule *m, Type *type, String name,
 		Type *variant = bt->Union.variants[j];
 
 		ptrdiff_t variant_index = j;
-		if (bt->Union.kind == UnionType_no_nil) {
+		if (bt->Union.kind != UnionType_no_nil) {
 			variant_index += 1;
 		}