rubocop: fix offences of the Style/AccessModifierDeclarations cop

This is a false positive documented in:
https://github.com/rubocop-hq/rubocop/issues/5953

spec/spec_helper.rb

@@ -13,8 +13,11 @@ if ENV["COVERAGE"]
 end
 
 class Module
+  # False positive: https://github.com/rubocop-hq/rubocop/issues/5953
+  # rubocop:disable Style/AccessModifierDeclarations
   public :remove_const
   public :remove_method
+  # rubocop:enable Style/AccessModifierDeclarations
 end
 
 Pad = Class.new do