message: Fix style reference in ToolTip.xaml (win)
diff: <ResourceDictionary.MergedDictionaries>
  <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/controls.tooltip.xaml" />
  </ResourceDictionary.MergedDictionaries>
  - <Style TargetType="ToolTip" BasedOn="{StaticResource MetroToolTip}">
  + <Style TargetType="ToolTip" BasedOn="{StaticResource MahApps.Styles.ToolTip}">
  <Setter Property="Background" Value="{DynamicResource Toggl.CardBackground}" />
  <Setter Property="BorderBrush" Value="{DynamicResource Toggl.PopupBorderBrush}" />
  <Setter Property="BorderThickness" Value="1" />
  