Coco: Tr::tr-ify one string

Change-Id: I332bd1d503c5e1f64b2116d996dd00ed56271759
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coco/cocoplugin.cpp

@@ -137,7 +137,7 @@ void CocoPlugin::initialize()
 
     IOptionsPage::registerCategory(
         "I.Coco",
-        QCoreApplication::translate("Coco", "Coco"),
+        Tr::tr("Coco"),
         ":/cocoplugin/images/SquishCoco_48x48.png");
 
     setupCocoSettings();