Add back Lint/UselessAssignment

Fix: #43169

.rubocop.yml

@@ -221,6 +221,9 @@ Lint/RedundantStringCoercion:
 Lint/UriEscapeUnescape:
   Enabled: true
 
+Lint/UselessAssignment:
+  Enabled: true
+
 Lint/DeprecatedClassMethods:
   Enabled: true
 

actiontext/lib/generators/action_text/install/install_generator.rb

@@ -9,7 +9,7 @@ module ActionText
       source_root File.expand_path("templates", __dir__)
 
       def install_javascript_dependencies
-        if using_node = Pathname(destination_root).join("package.json").exist?
+        if Pathname(destination_root).join("package.json").exist?
           say "Installing JavaScript dependencies", :green
           run "yarn add @rails/actiontext trix"
         end