extend test case to check inline markup extension syntax as well

ILSpy.BamlDecompiler/Tests/Cases/MarkupExtension.xaml

@@ -1,4 +1,4 @@
-<Label xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+<Label DataContext="{Binding Blub}" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
     <Label.Style>
         <Style />
     </Label.Style>