docs: add section titles

Author: kenjis

user_guide_src/source/libraries/sessions.rst

@@ -542,6 +542,9 @@ However, there are some conditions that must be met:
 
   - You can NOT use a persistent connection.
 
+Configure DatabaseHandler
+-------------------------
+
 In order to use the 'DatabaseHandler' session driver, you must also create this
 table that we already mentioned and then set it as your
 ``$savePath`` value.
@@ -623,6 +626,9 @@ bundled with PHP.
 Chances are, you're only be using the RedisHandler driver only if you're already
 both familiar with Redis and using it for other purposes.
 
+Configure RedisHandler
+----------------------
+
 Just as with the 'FileHandler' and 'DatabaseHandler' drivers, you must also configure
 the storage location for your sessions via the
 ``$savePath`` setting.
@@ -665,6 +671,9 @@ deleted after Y seconds have passed (but not necessarily that it won't
 expire earlier than that time). This happens very rarely, but should be
 considered as it may result in loss of sessions.
 
+Configure RedisHandler
+----------------------
+
 The ``$savePath`` format is fairly straightforward here,
 being just a ``host:port`` pair: