DEV: update syntax tree to latest (#24623)

update format to latest syntax tree

spec/requests/topics_controller_spec.rb

@@ -309,11 +309,11 @@ RSpec.describe TopicsController do
           begin
             called = false
 
-            assert = ->(original_topic, destination_topic) {
+            assert = ->(original_topic, destination_topic) do
               called = true
               expect(original_topic).to eq(topic)
               expect(destination_topic).to eq(dest_topic)
-            }
+            end
 
             DiscourseEvent.on(:topic_merged, &assert)