Fix documentation test

Author: nyalldawson

python/core/qgserror.sip

@@ -78,6 +78,9 @@ class QgsError
   public:
 
     QgsError();
+%Docstring
+Constructor for QgsError
+%End
 
     QgsError( const QString &message, const QString &tag );
 %Docstring

src/core/qgserror.h

@@ -84,6 +84,7 @@ class CORE_EXPORT QgsError
 {
   public:
 
+    //! Constructor for QgsError
     QgsError() = default;
 
     /**

src/plugins/qgsapplydialog.h

@@ -29,6 +29,8 @@ class QgsApplyDialog: public QDialog
     Q_OBJECT
 
   public:
+
+    //! Constructor for QgsApplyDialog
     QgsApplyDialog() = default;
 
     /**