Add temporary additional sample content to test against

Author: adamwathan

docs/components/MarkdownSample.mdx

@@ -31,7 +31,7 @@ Now we're going to try out a header style.
 
 ---
 
-## Lorem Ipsum is simply dummy text of the printing and typesetting industry.
+## Typography should be easy
 
 So that's a header for you — with any luck by the time I'm done writing this plugin that will look pretty reasonable.