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

config/locales/en.yml

@@ -1740,6 +1740,8 @@ en:
       self_vote: You cannot vote in your own polls
       too_few_options: must have more than one item
       too_many_options: can't contain more than %{max} items
+  posting_defaults:
+    explanation: These settings will be used as defaults when you create new posts, but you can edit them per post within the composer.
   preferences:
     other: Other
     posting_defaults: Posting defaults

config/navigation.rb

@@ -16,6 +16,7 @@ SimpleNavigation::Configuration.run do |navigation|
 
     n.item :preferences, safe_join([material_symbol('settings'), t('settings.preferences')]), settings_preferences_path, if: -> { current_user.functional? && !self_destruct } do |s|
       s.item :appearance, safe_join([material_symbol('computer'), t('settings.appearance')]), settings_preferences_appearance_path
+      s.item :posting_defaults, safe_join([material_symbol('edit_square'), t('preferences.posting_defaults')]), settings_preferences_posting_defaults_path
       s.item :notifications, safe_join([material_symbol('mail'), t('settings.notifications')]), settings_preferences_notifications_path
       s.item :other, safe_join([material_symbol('tune'), t('preferences.other')]), settings_preferences_other_path
     end

config/routes/settings.rb

@@ -9,6 +9,7 @@ namespace :settings do
 
   namespace :preferences do
     resource :appearance, only: [:show, :update], controller: :appearance
+    resource :posting_defaults, only: [:show, :update], controller: :posting_defaults
     resource :notifications, only: [:show, :update]
     resource :other, only: [:show, :update], controller: :other
   end