Update activity_type.cpp

addd withdrawal to activity type

src/activity_type.cpp

@@ -79,6 +79,7 @@ std::string enum_to_string<distraction_type>( distraction_type data )
  case distraction_type::temperature: return "temperature";
  case distraction_type::mutation: return "mutation";
  case distraction_type::oxygen: return "oxygen";
+ case distraction_type::withdrawal: return "withdrawal";
  // *INDENT-ON*
  default:
  cata_fatal( "Invalid distraction_type in enum_to_string" );