Merge pull request rails#49967 from p8/railties/test-env-show-exceptions-comment

Update description for show_exceptions in environments/test.rb

Author: jonathanhefner

railties/lib/rails/generators/rails/app/templates/config/environments/test.rb.tt

@@ -27,7 +27,7 @@ Rails.application.configure do
   config.action_controller.perform_caching = false
   config.cache_store = :null_store
 
-  # Raise exceptions instead of rendering exception templates.
+  # Render exception templates for rescuable exceptions and raise for other exceptions.
   config.action_dispatch.show_exceptions = :rescuable
 
   # Disable request forgery protection in test environment.