Rename error class, add ::Mcaptcha

Renamed the error class and added a new
include line ending with ::Mcaptcha to see
if that solves the unitialized constant error
Auth::CaptchaConcern::Mcaptcha since we've *definitely*
included the Mcaptcha::Adapters::ViewMethods

app/controllers/auth/confirmations_controller.rb

@@ -2,6 +2,7 @@
 
 class Auth::ConfirmationsController < Devise::ConfirmationsController
   include Auth::CaptchaConcern
+  include Auth::CaptchaConcern::Mcaptcha
 
   layout 'auth'
 

lib/mcaptcha/mcaptcha.rb

@@ -17,7 +17,7 @@ module Mcaptcha
   class McaptchaError < StandardError
   end
 
-  class VerifyError < HcaptchaError
+  class VerifyError < McaptchaError
   end
 
   # Gives access to the current Configuration.