Fix `ku` locale not being right-to-left (#15252)

app/helpers/application_helper.rb

@@ -7,6 +7,13 @@ module ApplicationHelper
     follow
   ).freeze
 
+  RTL_LOCALES = %i(
+    ar
+    fa
+    he
+    ku
+  ).freeze
+
   def active_nav_class(*paths)
     paths.any? { |path| current_page?(path) } ? 'active' : ''
   end
@@ -44,7 +51,7 @@ module ApplicationHelper
   end
 
   def locale_direction
-    if [:ar, :fa, :he].include?(I18n.locale)
+    if RTL_LOCALES.include?(I18n.locale)
       'rtl'
     else
       'ltr'