Update Index.rst, typos (#765)

Author: Cosmaeus

Documentation/Concepts/Backend/SiteManagement/Index.rst

@@ -8,7 +8,7 @@ Site Management modules
 
 The modules in this group manage and configure a site in your installation.
 
-It is possible to manage more then one web site within one TYPO3 installation.
+It is possible to manage more than one website within one TYPO3 installation.
 In the beginning you will probably only have one site in your installation.
 
 The following modules are available in a full TYPO3 installation: