fix typos

activerecord/test/cases/connection_pool_test.rb

@@ -329,7 +329,7 @@ def test_pool_sets_connection_visitor
       end
 
       # make sure exceptions are thrown when establish_connection
-      # is called with a anonymous class
+      # is called with an anonymous class
       def test_anonymous_class_exception
         anonymous = Class.new(ActiveRecord::Base)
         handler = ActiveRecord::Base.connection_handler