remove extra whitespace

Author: Larocceau

docs/recipes/ui/add-routing.md

@@ -1,6 +1,5 @@
 # How do I add routing to a SAFE app with a shared model for all pages?
 
-
 When building larger apps, you probably want different pages to be accessible through different URLs. In this recipe, we show you how to add routes to different pages to an application, including adding a "page not found" page that is displayed when an unknown URL is entered.
 
 In this recipe we use the simplest approach to storing states for multiple pages, by creating a single state for the full app. A potential benefit of this approach is that the state of a page is not lost when navigating away from it. You will see how that works at the end of the recipe.