note a deprecated test

Author: jamis

lib/mongoid/criteria/queryable/selectable.rb

@@ -496,6 +496,9 @@ def negating?
         # @example Add the $not criterion.
         #   Person.not(name: /Bob/)
         #
+        # @example Execute a $not in a where query.
+        #   Person.where(:name.not => /Bob/)
+        #
         # @example Negate a Criteria instance
         #   Person.not(Person.where(...))
         #

spec/mongoid/criteria/queryable/selectable_logical_spec.rb

@@ -1862,9 +1862,13 @@
         it_behaves_like 'returns a cloned query'
       end
 
+      # This context tests a deprecated syntax and behavior, and must be
+      # removed when the deprecated parameterless-not syntax is removed.
       context 'when the criterion are a double negative' do
         let(:selection) do
-          query.not.where(:first.not => /1/)
+          Mongoid.deprecator.silence do
+            query.not.where(:first.not => /1/)
+          end
         end
 
         it 'does not double the $not selector' do