Polish session auto-configuration

See gh-5158

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -356,6 +356,9 @@ content into your application; rather pick only the properties that you need.
 	spring.resources.chain.strategy.fixed.version= # Version string to use for the Version Strategy.
 	spring.resources.static-locations=classpath:/META-INF/resources/,classpath:/resources/,classpath:/static/,classpath:/public/ # Locations of static resources.
 
+    # SPRING SESSION ({sc-spring-boot-autoconfigure}/session/SocialWebAutoConfiguration.{sc-ext}[SessionAutoConfiguration])
+    spring.session.store.store-type= # Session store type
+
 	# SPRING SOCIAL ({sc-spring-boot-autoconfigure}/social/SocialWebAutoConfiguration.{sc-ext}[SocialWebAutoConfiguration])
 	spring.social.auto-connection-views=false # Enable the connection status view for supported providers.
 

spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc

@@ -4393,11 +4393,21 @@ class for more details.
 [[boot-features-session]]
 == Spring Session
 Spring Session provides support for managing a user's session information. If you are
-writing a web application and Spring Session and Spring Data Redis are both on the
-classpath, Spring Boot will auto-configure Spring Session through its
-`@EnableRedisHttpSession`. Session data will be stored in Redis and the session timeout
+writing a web application and Spring Session and one the following providers:
+
+* JDBC
+* Hazelcast
+* Spring Data Mongo
+* Spring Data Redis
+
+on the classpath, Spring Boot will auto-configure Spring Session through its
+`@EnableJdbcHttpSession`, `@EnableHazelcastHttpSession`, `@EnableMongoHttpSession`,
+`@EnableRedisHttpSession`. Session data will be stored in the provider and the session timeout
 can be configured using the `server.session.timeout` property.
 
+It is also possible to _force_ the session provider to use via the `spring.session.store.type`
+property.
+
 
 
 [[boot-features-jmx]]