QmlDesigner.Rewriter: setting textModifier to lastCorrectQmlSource

If rewrting fails we have to set back the textModifier

Reviewed-by: Erik Verbruggen

src/plugins/qmldesigner/core/model/rewriterview.cpp

@@ -438,6 +438,7 @@ void RewriterView::enterErrorState(const QString &errorMessage)
 
 void RewriterView::resetToLastCorrectQml()
 {
+    m_textModifier->textDocument()->setPlainText(lastCorrectQmlSource);
     ModelAmender differenceHandler(m_textToModelMerger.data());
     m_textToModelMerger->load(lastCorrectQmlSource.toUtf8(), differenceHandler);