Replace deprecated `STATS_DIRECTORIES` with `Rails::CodeStatistics.register_directory` approach (#33445)

config/initializers/statistics.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+[
+  %w(AppLibs app/lib),
+  %w(Policies app/policies),
+  %w(Presenters app/presenters),
+  %w(Serializers app/serializers),
+  %w(Services app/services),
+  %w(Validators app/validators),
+  %w(Workers app/workers),
+].each do |name, directory|
+  Rails::CodeStatistics.register_directory(name.titleize, directory)
+end

lib/tasks/statistics.rake

@@ -1,21 +0,0 @@
-# frozen_string_literal: true
-
-task stats: 'mastodon:stats'
-
-namespace :mastodon do
-  desc 'Report code statistics (KLOCs, etc)'
-  task :stats do
-    require 'rails/code_statistics'
-    [
-      ['App Libraries', 'app/lib'],
-      %w(Presenters app/presenters),
-      %w(Policies app/policies),
-      %w(Serializers app/serializers),
-      %w(Services app/services),
-      %w(Validators app/validators),
-      %w(Workers app/workers),
-    ].each do |name, dir|
-      STATS_DIRECTORIES << [name, dir]
-    end
-  end
-end