Convert all settings objects to the subclass of Config::Options

To support utility methods like `#to_h`, `#dig` and so on, this changes
the all settings objects to the subclass of Config::Options.

refs: ruby/gem_rbs_collection#636

lib/rbs_config/config.rb

@@ -23,10 +23,16 @@ def generate
         methods = generate_methods(config)
 
         format <<~RBS
-          class #{class_name}
-            #{classes.join("\n")}
-            #{methods.join("\n")}
+          module Config
+            module Generated
+              class #{class_name} < ::Config::Options
+                #{classes.join("\n")}
+                #{methods.join("\n")}
+              end
+            end
           end
+
+          #{class_name}: Config::Generated::#{class_name}
         RBS
       end
 
@@ -49,7 +55,7 @@ def generate_classes(config)
             methods = generate_methods(value)
 
             <<~RBS
-              class #{key.camelize}
+              class #{key.camelize} < ::Config::Options
                 #{classes.join("\n")}
                 #{methods.join("\n")}
               end
@@ -60,14 +66,14 @@ class #{key.camelize}
 
       def generate_methods(config)
         config.map do |key, value|
-          "def self.#{key}: () -> #{stringify_type(key, value)}"
+          "def #{key}: () -> #{stringify_type(key, value)}"
         end
       end
 
       def stringify_type(name, value)
         case value
         when Hash
-          "singleton(#{name.camelize})"
+          name.camelize
         when Array
           types = value.map { |v| stringify_type(name, v) }.uniq
           "Array[#{types.join(" | ")}]"

spec/rbs_config/config_spec.rb

@@ -31,21 +31,27 @@
     end
     let(:expected) do
       <<~RBS
-        class Settings
-          class Foo
-            def self.bar: () -> Integer
-            def self.baz: () -> bool
-          end
+        module Config
+          module Generated
+            class Settings < ::Config::Options
+              class Foo < ::Config::Options
+                def bar: () -> Integer
+                def baz: () -> bool
+              end
 
-          class Quux
-            def self.lorem: () -> Integer
-            def self.ipsum: () -> Integer
-          end
+              class Quux < ::Config::Options
+                def lorem: () -> Integer
+                def ipsum: () -> Integer
+              end
 
-          def self.foo: () -> singleton(Foo)
-          def self.qux: () -> Array[String]
-          def self.quux: () -> Array[singleton(Quux)]
+              def foo: () -> Foo
+              def qux: () -> Array[String]
+              def quux: () -> Array[Quux]
+            end
+          end
         end
+
+        Settings: Config::Generated::Settings
       RBS
     end