Move Servlet under RDoc::RI

This class is used as a server for the ri command, not as a rdoc server.
So putting it under RDoc::RI will make its purpose clearer.

Gemfile

@@ -11,4 +11,5 @@ group :development do
   gem 'rubocop', '>= 1.31.0'
   gem 'gettext'
   gem 'prism', '>= 0.30.0'
+  gem 'webrick'
 end

lib/rdoc.rb

@@ -162,7 +162,6 @@ def self.home
   autoload :Generator,      "#{__dir__}/rdoc/generator"
   autoload :Options,        "#{__dir__}/rdoc/options"
   autoload :Parser,         "#{__dir__}/rdoc/parser"
-  autoload :Servlet,        "#{__dir__}/rdoc/servlet"
   autoload :RI,             "#{__dir__}/rdoc/ri"
   autoload :Stats,          "#{__dir__}/rdoc/stats"
   autoload :Store,          "#{__dir__}/rdoc/store"

lib/rdoc/ri.rb

@@ -13,8 +13,9 @@ module RDoc::RI
 
   class Error < RDoc::Error; end
 
-  autoload :Driver, "#{__dir__}/ri/driver"
-  autoload :Paths,  "#{__dir__}/ri/paths"
-  autoload :Store,  "#{__dir__}/ri/store"
+  autoload :Driver,  "#{__dir__}/ri/driver"
+  autoload :Paths,   "#{__dir__}/ri/paths"
+  autoload :Store,   "#{__dir__}/ri/store"
+  autoload :Servlet, "#{__dir__}/ri/servlet"
 
 end

lib/rdoc/ri/driver.rb

@@ -1506,7 +1506,7 @@ def start_server
 
     extra_doc_dirs = @stores.map {|s| s.type == :extra ? s.path : nil}.compact
 
-    server.mount '/', RDoc::Servlet, nil, extra_doc_dirs
+    server.mount '/', RDoc::RI::Servlet, nil, extra_doc_dirs
 
     trap 'INT'  do server.shutdown end
     trap 'TERM' do server.shutdown end

lib/rdoc/servlet.rb → lib/rdoc/ri/servlet.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
-require_relative '../rdoc'
+require_relative '../../rdoc'
 require 'erb'
 require 'time'
 require 'json'
@@ -24,14 +24,14 @@
 #
 #   server = WEBrick::HTTPServer.new Port: 8000
 #
-#   server.mount '/', RDoc::Servlet
+#   server.mount '/', RDoc::RI::Servlet
 #
 # If you want to mount the servlet some other place than the root, provide the
 # base path when mounting:
 #
-#   server.mount '/rdoc', RDoc::Servlet, '/rdoc'
+#   server.mount '/rdoc', RDoc::RI::Servlet, '/rdoc'
 
-class RDoc::Servlet < WEBrick::HTTPServlet::AbstractServlet
+class RDoc::RI::Servlet < WEBrick::HTTPServlet::AbstractServlet
 
   @server_stores = Hash.new { |hash, server| hash[server] = {} }
   @cache         = Hash.new { |hash, store|  hash[store]  = {} }
@@ -146,7 +146,7 @@ def do_GET req, res
   # Fills in +res+ with the class, module or page for +req+ from +store+.
   #
   # +path+ is relative to the mount_path and is used to determine the class,
-  # module or page name (/RDoc/Servlet.html becomes RDoc::Servlet).
+  # module or page name (/RDoc/RI.html becomes RDoc::RI).
   # +generator+ is used to create the page.
 
   def documentation_page store, generator, path, req, res

rdoc.gemspec

@@ -208,8 +208,8 @@ RDoc includes the +rdoc+ and +ri+ tools for generating and displaying documentat
     "lib/rdoc/ri/paths.rb",
     "lib/rdoc/ri/store.rb",
     "lib/rdoc/ri/task.rb",
+    "lib/rdoc/ri/servlet.rb",
     "lib/rdoc/rubygems_hook.rb",
-    "lib/rdoc/servlet.rb",
     "lib/rdoc/single_class.rb",
     "lib/rdoc/stats.rb",
     "lib/rdoc/stats/normal.rb",

test/rdoc/test_rdoc_servlet.rb

@@ -30,7 +30,7 @@ def @server.mount(*) end
 
     @extra_dirs = [File.join(@tempdir, 'extra1'), File.join(@tempdir, 'extra2')]
 
-    @s = RDoc::Servlet.new @server, @stores, @cache, nil, @extra_dirs
+    @s = RDoc::RI::Servlet.new @server, @stores, @cache, nil, @extra_dirs
 
     @req = WEBrick::HTTPRequest.new :Logger => nil
     @res = WEBrick::HTTPResponse.new :HTTPVersion => '1.0'
@@ -141,7 +141,7 @@ def @req.path() raise 'no' end
   end
 
   def test_do_GET_mount_path
-    @s = RDoc::Servlet.new @server, @stores, @cache, '/mount/path'
+    @s = RDoc::RI::Servlet.new @server, @stores, @cache, '/mount/path'
 
     temp_dir do
       FileUtils.mkdir 'css'