Fix where.not with in clause

Arel::Nodes::In inherits from Arel::Nodes::Equality, so the case
statement was always using the Equality operator for both scenarios,
resulting in a not equal query instead.

activerecord/lib/active_record/relation/query_methods.rb

@@ -20,15 +20,15 @@ def initialize(scope)
       #    User.where.not(name: nil)
       #    # SELECT * FROM users WHERE name IS NOT NULL
       #
-      #    User.where.not(name: %(Ko1 Nobu))
+      #    User.where.not(name: %w(Ko1 Nobu))
       #    # SELECT * FROM users WHERE name NOT IN ('Ko1', 'Nobu')
       def not(opts, *rest)
         where_value = @scope.send(:build_where, opts, rest).map do |rel|
           case rel
-          when Arel::Nodes::Equality
-            Arel::Nodes::NotEqual.new(rel.left, rel.right)
           when Arel::Nodes::In
             Arel::Nodes::NotIn.new(rel.left, rel.right)
+          when Arel::Nodes::Equality
+            Arel::Nodes::NotEqual.new(rel.left, rel.right)
           when String
             Arel::Nodes::Not.new(Arel::Nodes::SqlLiteral.new(rel))
           else

activerecord/test/cases/relation/where_chain_test.rb

@@ -19,7 +19,7 @@ def test_not_null
     end
 
     def test_not_in
-      expected = Arel::Nodes::NotEqual.new(Post.arel_table[:title], %w[hello goodbye])
+      expected = Arel::Nodes::NotIn.new(Post.arel_table[:title], %w[hello goodbye])
       relation = Post.where.not(title: %w[hello goodbye])
       assert_equal([expected], relation.where_values)
     end