TextEditor: One more missing dialog parent.

Change-Id: I9dab955a0b4a0d7d83a69cfc474633be43e7169f
Reviewed-by: David Schulz <david.schulz@digia.com>

src/plugins/texteditor/codestylepool.cpp

@@ -290,6 +290,6 @@ void CodeStylePool::exportCodeStyle(const Utils::FileName &fileName, ICodeStyleP
     tmp.insert(QLatin1String(displayNameKey), codeStyle->displayName());
     tmp.insert(QLatin1String(codeStyleDataKey), map);
     Utils::PersistentSettingsWriter writer(fileName, QLatin1String(codeStyleDocKey));
-    writer.save(tmp, 0);
+    writer.save(tmp, Core::ICore::mainWindow());
 }