TextEditor: Merge the two sets of *EditorWidget constructors

Change-Id: I45d87d0be722ac36d64af222f03f8cb76242c9df
Reviewed-by: Christian Stenger <christian.stenger@digia.com>

src/plugins/diffeditor/diffeditor.cpp

@@ -101,8 +101,9 @@ private:
 };
 
 DescriptionEditorWidget::DescriptionEditorWidget(QWidget *parent)
-    : BaseTextEditorWidget(new BaseTextDocument, parent)
+    : BaseTextEditorWidget(parent)
 {
+    setTextDocument(BaseTextDocumentPtr(new BaseTextDocument));
     DisplaySettings settings = displaySettings();
     settings.m_textWrapping = false;
     settings.m_displayLineNumbers = false;