Merge pull request rails#43560 from c960657/action-mailer-docs

ActionMailer: Document delivery_job and deliver_later_queue_name

Author: kaspth

actionmailer/lib/action_mailer/base.rb

@@ -435,6 +435,9 @@ module ActionMailer
   # * <tt>deliveries</tt> - Keeps an array of all the emails sent out through the Action Mailer with
   #   <tt>delivery_method :test</tt>. Most useful for unit and functional testing.
   #
+  # * <tt>delivery_job</tt> - The job class used with <tt>deliver_later</tt>. Defaults to
+  #   +ActionMailer::MailDeliveryJob+.
+  #
   # * <tt>deliver_later_queue_name</tt> - The name of the queue used with <tt>deliver_later</tt>.
   class Base < AbstractController::Base
     include DeliveryMethods

guides/source/action_mailer_basics.md

@@ -810,6 +810,8 @@ files (environment.rb, production.rb, etc...)
 |`delivery_method`|Defines a delivery method. Possible values are:<ul><li>`:smtp` (default), can be configured by using `config.action_mailer.smtp_settings`.</li><li>`:sendmail`, can be configured by using `config.action_mailer.sendmail_settings`.</li><li>`:file`: save emails to files; can be configured by using `config.action_mailer.file_settings`.</li><li>`:test`: save emails to `ActionMailer::Base.deliveries` array.</li></ul>See [API docs](https://api.rubyonrails.org/classes/ActionMailer/Base.html) for more info.|
 |`perform_deliveries`|Determines whether deliveries are actually carried out when the `deliver` method is invoked on the Mail message. By default they are, but this can be turned off to help functional testing. If this value is `false`, `deliveries` array will not be populated even if `delivery_method` is `:test`.|
 |`deliveries`|Keeps an array of all the emails sent out through the Action Mailer with delivery_method :test. Most useful for unit and functional testing.|
+|`delivery_job`|The job class used with `deliver_later`. Defaults to `ActionMailer::MailDeliveryJob`.|
+|`deliver_later_queue_name`|The name of the queue used with `deliver_later`.|
 |`default_options`|Allows you to set default values for the `mail` method options (`:from`, `:reply_to`, etc.).|
 
 For a complete writeup of possible configurations see the