message: Manifests: Remove support for declaring features as lists
  It is not used and not described in the docs
diff: @@ -641,51 +641,12 @@ namespace vcpkg
  constexpr StringLiteral FeatureDeserializer::DESCRIPTION;
  constexpr StringLiteral FeatureDeserializer::DEPENDENCIES;
  - struct ArrayFeatureDeserializer : Json::IDeserializer<std::unique_ptr<FeatureParagraph>>
  - {
  - virtual StringView type_name() const override { return "a feature"; }
  -
  - virtual Span<const StringView> valid_fields() const override
  - {
  - static const StringView t[] = {
  - FeatureDeserializer::NAME,
  - FeatureDeserializer::DESCRIPTION,
  - FeatureDeserializer::DEPENDENCIES,
  - };
  - return t;
  - }
  -
  - virtual Optional<std::unique_ptr<FeatureParagraph>> visit_object(Json::Reader& r,
  - const Json::Object& obj) override
  - {
  - std::string name;
  - r.required_object_field(
  - type_name(), obj, FeatureDeserializer::NAME, name, Json::IdentifierDeserializer::instance);
  - auto opt = FeatureDeserializer::instance.visit_object(r, obj);
  - if (auto p = opt.get())
  - {
  - p->get()->name = std::move(name);
  - }
  - return opt;
  - }
  -
  - static Json::ArrayDeserializer<ArrayFeatureDeserializer> array_instance;
  - };
  - Json::ArrayDeserializer<ArrayFeatureDeserializer> ArrayFeatureDeserializer::array_instance{
  - "an array of feature objects"};
  -
  struct FeaturesFieldDeserializer : Json::IDeserializer<std::vector<std::unique_ptr<FeatureParagraph>>>
  {
  virtual StringView type_name() const override { return "a set of features"; }
  virtual Span<const StringView> valid_fields() const override { return {}; }
  - virtual Optional<std::vector<std::unique_ptr<FeatureParagraph>>> visit_array(Json::Reader& r,
  - const Json::Array& arr) override
  - {
  - return ArrayFeatureDeserializer::array_instance.visit_array(r, arr);
  - }
  -
  virtual Optional<std::vector<std::unique_ptr<FeatureParagraph>>> visit_object(Json::Reader& r,
  const Json::Object& obj) override
  {
  