Merge pull request rails#30628 from yhirano55/add_local_option_to_message_form

Add local option to Message form [ci skip]

Author: kamipo

activestorage/README.md

@@ -63,7 +63,7 @@ end
 ```
 
 ```erb
-<%= form_with model: @message do |form| %>
+<%= form_with model: @message, local: true do |form| %>
   <%= form.text_field :title, placeholder: "Title" %><br>
   <%= form.text_area :content %><br><br>