Review fixes

- Move the parser to definition to `discover.rb`
- Move the rdoc plugin files to rdoc_plugin directory
- Rename files
- Rewrite signatures for the above changes

Author: raosush

lib/rdoc/discover.rb

@@ -0,0 +1,18 @@
+begin
+  gem 'rdoc', '~> 6.4.0'
+  require 'rdoc_plugin/parser'
+  module RDoc
+    class Parser
+      class RBS < Parser
+        parse_files_matching(/\.rbs$/)
+        def scan
+          ::RBS::RDocPlugin::Parser.new(@top_level, @content).scan
+        end
+      end
+    end
+  end
+rescue Gem::LoadError
+    # Error :sad:
+rescue Exception
+    # Exception :sad:
+end

lib/rdoc_plugin/discover.rb

@@ -2,23 +2,11 @@
 
 require 'rbs'
 
-module RDoc
-  class Parser
-    class RBS < Parser
-      parse_files_matching(/\.rbs$/)
-
-      def scan
-        ::RBS::RDocPlugin::Parser.new(@top_level, @content).scan
-      end
-    end
-  end
-end
-
 module RBS
   module RDocPlugin
     class Parser
 
-      attr_reader :top_level, :content
+      attr_accessor :top_level, :content
 
       def initialize(top_level, content)
         @top_level = top_level

lib/rdoc/parser/rbs.rb renamed to lib/rdoc_plugin/parser.rb

@@ -1,3 +1,10 @@
+module RDoc
+  class Parser
+    class RBS < Parser
+    end
+  end
+end
+
 module RBS
   module RDocPlugin
     class Parser

sig/rdoc/rbs.rbs

@@ -109,9 +109,6 @@ module RDoc
     def initialize: (RDoc::TopLevel top_level, String filename, String content, Hash[untyped, untyped] options, RDoc::Stats stats) -> void
 
     def scan: () -> RDoc::TopLevel
-
-    class RBS < Parser
-    end
   end
 
   # <!-- rdoc-file=lib/rdoc/code_object.rb -->

stdlib/rdoc/0/rdoc.rbs

@@ -1,10 +1,8 @@
 require "test_helper"
 
-require "tempfile"
+require "rdoc_plugin/parser"
 
-require "rdoc/parser/rbs"
-
-class RBSParserTest < Test::Unit::TestCase
+class RDocPluginParserTest < Test::Unit::TestCase
   def parser(content)
     top_level = RDoc::TopLevel.new("a.rbs")
     top_level.store = RDoc::Store.new()