Fix remaining errors

Author: m-kuhn

python/core/qgsexpression.sip

@@ -1134,7 +1134,7 @@ The name of the column.
  :rtype: str
 %End
 
-        virtual NodeType nodeType() const;
+        virtual QgsExpression::NodeType nodeType() const;
         virtual bool prepare( QgsExpression *parent, const QgsExpressionContext *context );
         virtual QVariant eval( QgsExpression *parent, const QgsExpressionContext *context );
         virtual QString dump() const;

src/core/qgsexpression.h

@@ -1180,7 +1180,7 @@ class CORE_EXPORT QgsExpression
         //! The name of the column.
         QString name() const { return mName; }
 
-        virtual NodeType nodeType() const override { return ntColumnRef; }
+        virtual QgsExpression::NodeType nodeType() const override { return ntColumnRef; }
         virtual bool prepare( QgsExpression *parent, const QgsExpressionContext *context ) override;
         virtual QVariant eval( QgsExpression *parent, const QgsExpressionContext *context ) override;
         virtual QString dump() const override;