Say 'Error', not 'Not allowed' in listing comments

chapters/classes.tex

@@ -901,7 +901,7 @@ \section{Specialized Classes}\doublelabel{specialized-classes}
    end '*';
 end Complex;
 record MyComplex
-  extends Complex; // not allowed, since extending from enclosing scope
+  extends Complex; // Error; extending from enclosing scope.
   Real k;
 end MyComplex;
 operator record ComplexVoltage = Complex(re(unit="V"),im(unit="V")); // allowed

chapters/connectors.tex

@@ -228,7 +228,7 @@ \subsection{Expandable Connectors}\doublelabel{expandable-connectors}
 import Interfaces=Modelica.Electrical.Analog.Interfaces;
 expandable connector ElectricalBus
   Interfaces.PositivePin p12, n12; // OK
-  flow Modelica.Units.SI.Current i; // not allowed
+  flow Modelica.Units.SI.Current i; // Error
 end ElectricalBus;
 
 model Battery
@@ -259,14 +259,9 @@ \subsection{Expandable Connectors}\doublelabel{expandable-connectors}
   EmptyBus bus2;
   RealInput speed;
 equation
-  connect(speed, bus1.speed); // ok, only one undeclared
-  // and it is unsubscripted
-
-  connect(bus1.pressure, bus2.pressure);
-  // not allowed, both undeclared
-
-  connect(speed, bus2.speed[2]);
-  // introduces speed array (with element [2]).
+  connect(speed, bus1.speed); // OK; only one undeclared and not subscripted.
+  connect(bus1.pressure, bus2.pressure); // Error; both undeclared.
+  connect(speed, bus2.speed[2]); // Introduces speed array (with element [2]).
 end Controller;
 \end{lstlisting}
 \end{example}