Suppress a RuboCop offense

This PR suppresses the following RuboCop offense:

```console
$ bundle exec rubocop -a
(snip)

Offenses:

lib/rubocop/cop/rails/save_bang.rb:247:11: C: [Corrected] InternalAffairs/OperatorKeyword: Use node.operator_keyword?.
node.or_type? || node.and_type? || single_negative?(node)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```

Author: koic

lib/rubocop/cop/rails/save_bang.rb

@@ -244,7 +244,7 @@ def in_condition_or_compound_boolean?(node)
         end
 
         def operator_or_single_negative?(node)
-          node.or_type? || node.and_type? || single_negative?(node)
+          node.operator_keyword? || single_negative?(node)
         end
 
         def conditional?(parent)