Signals: Add variable for restriction info, add bit for reserve through

src/newgrf_extension.h

@@ -61,6 +61,8 @@ enum Action2VariableRemapIds {
 	A2VRI_OBJECT_FOUNDATION_SLOPE = 0x100,
 	A2VRI_OBJECT_FOUNDATION_SLOPE_CHANGE,
 	A2VRI_VEHICLE_CURRENT_SPEED_SCALED,
+	A2VRI_RAILTYPE_SIGNAL_RESTRICTION_INFO,
+	A2VRI_SIGNALS_SIGNAL_RESTRICTION_INFO,
 };
 
 /** Action14 feature definition */