Merge pull request #17869 from 2called-chaos/patch-1

Fix documentation for ActionMailer::Base#default [ci skip]

actionmailer/lib/action_mailer/base.rb

@@ -493,7 +493,7 @@ def mailer_name
 
       # Sets the defaults through app configuration:
       #
-      #     config.action_mailer.default { from: "no-reply@example.org" }
+      #     config.action_mailer.default(from: "no-reply@example.org")
       #
       # Aliased by ::default_options=
       def default(value = nil)