Fix broken list on the "Using packages" page (#12594)

Fixes the list here:
https://docs.flutter.dev/packages-and-plugins/using-packages#css-example

Author: loic-sharma

src/content/packages-and-plugins/using-packages.md

@@ -416,10 +416,10 @@ To use this package:
     }
     ```
 
-[`css_colors`]: {{site.pub-pkg}}/css_colors
-
 1. Run the app. The app's background should now be orange.
 
+[`css_colors`]: {{site.pub-pkg}}/css_colors
+
 ### Example: Using the url_launcher package to launch the browser {:#url-example}
 
 The [`url_launcher`][] plugin package enables opening