trivial changes to the intro

docs/index.rst

@@ -1,7 +1,7 @@
 Welcome to Flatpak's documentation!
 ===================================
 
-This covers everything you need to know to build and distribute applications as Flatpaks. The docs start with introduction to the basic concepts and a simple app building tutorial, before moving on to cover automated building and repository hosting.
+This documentation covers everything you need to know to build and distribute applications as Flatpaks. They start with an introduction to the basic concepts and a simple app building tutorial, before moving on to cover automated building and repository hosting.
 
 Example tutorials are used throughout. To complete them, it is necessary to have ``flatpak`` and ``flatpak-builder`` installed on your system. The Flatpak website provides `details on how to do this <http://flatpak.org/getting.html>`_.