Utils: Replace foreach with range-based for

Change-Id: I9aeea9c029ffc56cbadc04edd20e9b35b154f986
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/stylehelper.cpp

@@ -187,7 +187,8 @@ void StyleHelper::setBaseColor(const QColor &newcolor)
 
     if (color.isValid() && color != m_baseColor) {
         m_baseColor = color;
-        foreach (QWidget *w, QApplication::topLevelWidgets())
+        const QList<QWidget *> widgets = QApplication::topLevelWidgets();
+        for (QWidget *w : widgets)
             w->update();
     }
 }