Restore original header for browser version guards

Author: fxn

guides/source/7_2_release_notes.md

@@ -55,7 +55,7 @@ rails devcontainer
 
 For more information, see the [Getting Started with Dev Containers](https://edgeguides.rubyonrails.org/getting_started_with_devcontainer.html) guide.
 
-### Browser version guards
+### Add browser version guard by default
 
 Rails now adds the ability to specify the browser versions that will be allowed to access all actions
 (or some, as limited by `only:` or `except:`).
@@ -87,6 +87,8 @@ class MessagesController < ApplicationController
 end
 ```
 
+Newly generated applications have this guard set in `ApplicationController`.
+
 For more information, see the [allow_browser](https://api.rubyonrails.org/classes/ActionController/AllowBrowser/ClassMethods.html#method-i-allow_browser)
 documentation.