remove useless comma

Author: xabbuh

book/http_cache.rst

@@ -882,7 +882,7 @@ that data from its cache.
 
     If you want to use cache invalidation, have a look at the
     `FOSHttpCacheBundle`_. This bundle provides services to help with various
-    cache invalidation concepts, and also documents the configuration for a
+    cache invalidation concepts and also documents the configuration for a
     couple of common caching proxies.
 
 If one content corresponds to one URL, the ``PURGE`` model works well.