Merge branch '5.0' into 5.1

* 5.0:
  [Session] Removed another reference to a non-existent document

Author: javiereguiluz

session.rst

@@ -218,7 +218,6 @@ More about Sessions
 .. toctree::
     :maxdepth: 1
 
-    session/avoid_session_start
     session/database
     session/locale_sticky_session
     session/php_bridge