Per review, fix a some minor issues

app/controllers/checkout_controller.rb

@@ -80,7 +80,7 @@ class CheckoutController < BaseController
 
     # Redeem VINE voucher
     vine_voucher_redeemer = Vine::VoucherRedeemerService.new(order: @order)
-    if vine_voucher_redeemer.redeem == false
+    unless vine_voucher_redeemer.redeem
       # rubocop:disable Rails/DeprecatedActiveModelErrorsMethods
       flash[:error] = if vine_voucher_redeemer.errors.keys.include?(:redeeming_failed)
                         vine_voucher_redeemer.errors[:redeeming_failed]

spec/requests/spree/admin/payments_spec.rb

@@ -47,7 +47,7 @@ RSpec.describe Spree::Admin::PaymentsController, type: :request do
       end
     end
 
-    context "when a getway error happens" do
+    context "when a gateway error happens" do
       let(:payment_method) do
         create(:stripe_sca_payment_method, distributors: [order.distributor])
       end