add 30xx effect to hard reset envelope

currently only for 2612!

src/engine/platform/arcade.cpp

@@ -132,6 +132,9 @@ const char* DivPlatformArcade::getEffectName(unsigned char effect) {
     case 0x1f:
       return "1Fxx: Set PM depth (0 to 7F)";
       break;
+    case 0x30:
+      return "30xx: Toggle hard envelope reset on new notes";
+      break;
   }
   return NULL;
 }