removed unused blank lines and revert test

lib/rdoc/rubygems_hook.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
-
 require 'rubygems/user_interaction'
 require 'fileutils'
-
 require_relative '../rdoc'
 
 # We define the following two similar name classes in this file:
@@ -284,7 +282,7 @@ def remove
       # Do nothing if this is NOT a default gem.
       return unless self.class.default_gem?
 
-      # Remove generate document for compatibility if this is a
+      # Remove generated document for compatibility if this is a
       # default gem.
       RubyGemsHook.new(@spec).remove
     end

test/rdoc/test_rdoc_rubygems_hook.rb

@@ -2,16 +2,9 @@
 require 'rubygems'
 require 'fileutils'
 require 'tmpdir'
+require_relative '../../lib/rdoc/rubygems_hook'
 require 'test/unit'
 
-# This test requires lib/rubygems_plugin.rb .
-# To execute this test under a ruby-core, lib/rubygems_plugin.rb should be synced to ruby/ruby.
-# But I don't do so and skip this test under the situation because of avoiding ambiguity about rubygems_plugins on ruby/ruby.
-begin
-  require_relative '../../lib/rubygems_plugin'
-rescue LoadError
-end
-
 class TestRDocRubyGemsHook < Test::Unit::TestCase
   def setup
     @a = Gem::Specification.new do |s|
@@ -291,4 +284,4 @@ def test_setup_unwritable
     end
   end
 
-end if defined?(RDoc::RubyGemsHook)
+end