Use method_name instead of method when generating hash warnings

In #865 we introduced a `method_name` method on `MethodDescription` to avoid this bug, but the commit didn't actually use that method.  Sometimes the `@controller_method` object used is a `Apipie::Generator::Swagger::MethodDescription::Decorator` which is a `SimpleDelegate` onto a `Apipie::MethodDescription` and we'd expect to be able to call `method` on it, but unfortunately `method` is one of the things _not_ delegated by `SimpleDelegate` because it's a standard ruby method and so you get

    ArgumentError: wrong number of arguments (given 0, expected 1)

when you try to call it.  Using `method_name` instead avoids that so that's what we do - and now we can happily generate the swagger warnings when we have hash type objects without defined params.

lib/apipie/generator/swagger/param_description/type.rb

@@ -114,7 +114,7 @@ def validator
   def warn_hash_without_internal_typespec
     method_id =
       if @param_description.is_a?(Apipie::ResponseDescriptionAdapter::PropDesc)
-        @controller_method.method
+        @controller_method.method_name
       else
         Apipie::Generator::Swagger::MethodDescription::Decorator.new(@param_description.method_description).ruby_name
       end

spec/lib/apipie/generator/swagger/param_description/type_spec.rb

@@ -63,9 +63,11 @@
     )
   end
 
+  let(:controller_method) { 'index' }
+
   let(:type_definition) do
     described_class.
-      new(param_description, with_null: with_null, controller_method: 'index').
+      new(param_description, with_null: with_null, controller_method: controller_method).
       to_hash
   end
 
@@ -178,6 +180,22 @@
       it 'outputs a hash without internal typespec warning' do
         expect { subject }.to output(/is a generic Hash without an internal type specification/).to_stderr
       end
+
+      context 'and param is a prop desc with a delegated controller method' do
+        let(:param_description) do
+          Apipie.prop(param_description_name, 'object', {}, [])
+        end
+
+        let(:controller_method) do
+          Apipie::Generator::Swagger::MethodDescription::Decorator.new(
+            method_desc
+          )
+        end
+
+        it 'outputs a hash without internal typespec warning' do
+          expect { subject }.to output(/is a generic Hash without an internal type specification/).to_stderr
+        end
+      end
     end
   end
 end