Merge pull request rails#54702 from fatkodima/fix-action_mailer-default_options-docs

Fix `ActionMailer::Base.default` docs [skip-ci]

Author: fatkodima

actionmailer/lib/action_mailer/base.rb

@@ -574,18 +574,13 @@ def mailer_name
       attr_writer :mailer_name
       alias :controller_path :mailer_name
 
-      # Sets the defaults through app configuration:
-      #
-      #     config.action_mailer.default(from: "[email protected]")
+      # Allows to set defaults through app configuration:
       #
-      # Aliased by ::default_options=
+      #    config.action_mailer.default_options = { from: "[email protected]" }
       def default(value = nil)
         self.default_params = default_params.merge(value).freeze if value
         default_params
       end
-      # Allows to set defaults through app configuration:
-      #
-      #    config.action_mailer.default_options = { from: "[email protected]" }
       alias :default_options= :default
 
       # Wraps an email delivery inside of ActiveSupport::Notifications instrumentation.