Move config injection to own file

lib/rubocop/markdown.rb

@@ -9,6 +9,7 @@ module Markdown
     PROJECT_ROOT   = Pathname.new(__dir__).parent.parent.expand_path.freeze
     CONFIG_DEFAULT = PROJECT_ROOT.join("config", "default.yml").freeze
 
+    require_relative "markdown/inject"
     require_relative "markdown/preprocess"
     require_relative "markdown/rubocop_ext" if defined?(::RuboCop::ProcessedSource)
   end

lib/rubocop/markdown/inject.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Markdown
+    # Merge markdown config into default configuration
+    # See https://github.com/rubocop/rubocop-rspec/blob/master/lib/rubocop/rspec/inject.rb
+    module Inject # :nodoc:
+      def self.defaults!
+        path = CONFIG_DEFAULT.to_s
+        hash = ConfigLoader.send(:load_yaml_configuration, path)
+        config = RuboCop::Config.new(hash, path)
+        puts "configuration from #{path}" if ConfigLoader.debug?
+        config = ConfigLoader.merge_with_default(config, path)
+        ConfigLoader.instance_variable_set(:@default_configuration, config)
+      end
+    end
+  end
+end

lib/rubocop/markdown/rubocop_ext.rb

@@ -26,25 +26,14 @@ module Markdown # :nodoc:
     class << self
       attr_accessor :config_store
 
-      # Merge markdown config into default configuration
-      # See https://github.com/backus/rubocop-rspec/blob/master/lib/rubocop/rspec/inject.rb
-      def inject!
-        path = CONFIG_DEFAULT.to_s
-        hash = ConfigLoader.send(:load_yaml_configuration, path)
-        config = Config.new(hash, path)
-        puts "configuration from #{path}" if ConfigLoader.debug?
-        config = ConfigLoader.merge_with_default(config, path)
-        ConfigLoader.instance_variable_set(:@default_configuration, config)
-      end
-
       def markdown_file?(file)
         MARKDOWN_EXTENSIONS.include?(File.extname(file))
       end
     end
   end
 end
 
-RuboCop::Markdown.inject!
+RuboCop::Markdown::Inject.defaults!
 
 RuboCop::Runner.prepend(Module.new do
   # Set config store for Markdown