title: Add newline to Stringformat in XAML
body: <p>I'm binding the columnheaders of a datagrid to an observablecollection of dates, to display the day and date in the columnheader. This works fine. However, I would like to add a newline or break using the string. How can this be done?</p>
  
  <pre><code>&lt;DataGridTextColumn&gt;
      &lt;DataGridTextColumn.HeaderTemplate&gt;
          &lt;DataTemplate&gt;
              &lt;TextBlock TextWrapping="Wrap" Text="{Binding DataContext.Week.Days[1].Date, StringFormat=ddd dd.MM.yyyy, RelativeSource={RelativeSource AncestorType=DataGrid}}"/&gt;
  </code></pre>
  
  <p>This displays the following Text: Tue 06.12.2016 
  What I want it to display is </p>
  
  <p>Tue<br>
  06.12.2016 </p>