Add ActionText.deprecator

This commit adds `ActionText.deprecator`, and adds it to
`Rails.application.deprecators` so that it can be configured via
settings such as `config.active_support.report_deprecations`.

actiontext/lib/action_text.rb

@@ -3,6 +3,8 @@
 require "active_support"
 require "active_support/rails"
 
+require "action_text/deprecator"
+
 require "nokogiri"
 
 module ActionText

actiontext/lib/action_text/deprecator.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module ActionText
+  def self.deprecator # :nodoc:
+    @deprecator ||= ActiveSupport::Deprecation.new
+  end
+end

actiontext/lib/action_text/engine.rb

@@ -19,6 +19,10 @@ module ActionText
       #{root}/app/models
     )
 
+    initializer "action_text.deprecator" do |app|
+      app.deprecators[:action_text] = ActionText.deprecator
+    end
+
     initializer "action_text.attribute" do
       ActiveSupport.on_load(:active_record) do
         include ActionText::Attribute

railties/test/application/configuration_test.rb

@@ -3895,6 +3895,7 @@ module ApplicationTests
       assert_equal ActionDispatch.deprecator, Rails.application.deprecators[:action_dispatch]
       assert_equal ActionMailbox.deprecator, Rails.application.deprecators[:action_mailbox]
       assert_equal ActionMailer.deprecator, Rails.application.deprecators[:action_mailer]
+      assert_equal ActionText.deprecator, Rails.application.deprecators[:action_text]
       assert_equal ActionView.deprecator, Rails.application.deprecators[:action_view]
       assert_equal ActiveJob.deprecator, Rails.application.deprecators[:active_job]
       assert_equal ActiveRecord.deprecator, Rails.application.deprecators[:active_record]