Move posting defaults to their own preferences sub-category (#35966)

app/controllers/settings/preferences/posting_defaults_controller.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class Settings::Preferences::PostingDefaultsController < Settings::Preferences::BaseController
+  private
+
+  def after_update_redirect_path
+    settings_preferences_posting_defaults_path
+  end
+end