Add what's next to new sections

This commit also moves hazelcast from core features to IO

Closes gh-27132

spring-boot-project/spring-boot-docs/src/docs/asciidoc/container-images.adoc

@@ -9,3 +9,5 @@ include::container-images/efficient-images.adoc[]
 include::container-images/dockerfiles.adoc[]
 
 include::container-images/cloud-native-buildpacks.adoc[]
+
+include::container-images/whats-next.adoc[]

spring-boot-project/spring-boot-docs/src/docs/asciidoc/container-images/whats-next.adoc

@@ -0,0 +1,5 @@
+[[container-images.whats-next]]
+== What to Read Next
+Once you've learned how to build efficient container images, you can read about <<deployment#deployment.cloud.kubernetes, deploying applications to a cloud platform>>, such as Kubernetes.
+
+

spring-boot-project/spring-boot-docs/src/docs/asciidoc/data.adoc

@@ -6,4 +6,6 @@ Spring Boot integrates with a number of data technologies, both SQL and NoSQL.
 
 include::data/sql.adoc[]
 
-include::data/nosql.adoc[]
+include::data/nosql.adoc[]
+
+include::data/whats-next.adoc[]

spring-boot-project/spring-boot-docs/src/docs/asciidoc/data/whats-next.adoc

@@ -0,0 +1,4 @@
+[[data.whats-next]]
+== What to Read Next
+You should now have a feeling for how to use Spring Boot with various data technologies.
+From here, you can read about Spring Boot's support for various <<messaging#messaging, messaging technolgoies>> and how to enable them in your application.

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

@@ -22,8 +22,6 @@ include::features/internationalization.adoc[]
 
 include::features/json.adoc[]
 
-include::features/hazelcast.adoc[]
-
 include::features/task-execution-and-scheduling.adoc[]
 
 include::features/testing.adoc[]

spring-boot-project/spring-boot-docs/src/docs/asciidoc/io.adoc

@@ -9,9 +9,11 @@ We'll also cover calling remote REST or SOAP services and sending email.
 
 include::io/caching.adoc[]
 
+include::io/hazelcast.adoc[]
+
 include::io/quartz.adoc[]
 
-include::io/mail.adoc[]
+include::io/email.adoc[]
 
 include::io/validation.adoc[]
 
@@ -19,4 +21,6 @@ include::io/rest-client.adoc[]
 
 include::io/webservices.adoc[]
 
-include::io/jta.adoc[]
+include::io/jta.adoc[]
+
+include::io/whats-next.adoc[]

spring-boot-project/spring-boot-docs/src/docs/asciidoc/io/caching.adoc

@@ -98,7 +98,7 @@ Even if the JSR-107 standard does not enforce a standardized way to define the l
 
 NOTE: When a cache library offers both a native implementation and JSR-107 support, Spring Boot prefers the JSR-107 support, so that the same features are available if you switch to a different JSR-107 implementation.
 
-TIP: Spring Boot has <<features#features.hazelcast,general support for Hazelcast>>.
+TIP: Spring Boot has <<io#io.hazelcast,general support for Hazelcast>>.
 If a single `HazelcastInstance` is available, it is automatically reused for the `CacheManager` as well, unless the configprop:spring.cache.jcache.config[] property is specified.
 
 There are two ways to customize the underlying `javax.cache.cacheManager`:
@@ -130,7 +130,7 @@ An alternate configuration file can be provided as well, as shown in the followi
 
 [[io.caching.provider.hazelcast]]
 ==== Hazelcast
-Spring Boot has <<features#features.hazelcast,general support for Hazelcast>>.
+Spring Boot has <<io#io.hazelcast,general support for Hazelcast>>.
 If a `HazelcastInstance` has been auto-configured, it is automatically wrapped in a `CacheManager`.
 
 

spring-boot-project/spring-boot-docs/src/docs/asciidoc/io/hazelcast.adoc

@@ -1,4 +1,4 @@
-[[features.hazelcast]]
+[[io.hazelcast]]
 == Hazelcast
 If https://hazelcast.com/[Hazelcast] is on the classpath and a suitable configuration is found, Spring Boot auto-configures a `HazelcastInstance` that you can inject in your application.
 

spring-boot-project/spring-boot-docs/src/docs/asciidoc/io/whats-next.adoc

@@ -0,0 +1,6 @@
+[[io.whats-next]]
+== What to Read Next
+You should now have a good understanding of Spring Boot's <<features#features, core features>> and the various technologies that Spring Boot provides support for via auto-configuration.
+
+The next few sections go into detail about deploying applications to cloud platforms.
+You can read about <<container-images#container-images, building container images>> in the next section or skip to the <<actuator#actuator, production-ready features>> section.

spring-boot-project/spring-boot-docs/src/docs/asciidoc/messaging.adoc

@@ -19,6 +19,8 @@ include::messaging/rsocket.adoc[]
 
 include::messaging/spring-integration.adoc[]
 
+include::messaging/whats-next.adoc[]
+
 
 
 

spring-boot-project/spring-boot-docs/src/docs/asciidoc/messaging/whats-next.adoc

@@ -0,0 +1,4 @@
+[[messaging.whats-next]]
+== What to Read Next
+The next section describes how to enable <<io#io, IO capabilities>> in your applicaiton.
+You can read about <<io#io.caching, caching>>, <<io#io.email, mail>>, <<io#io.validation, validation>>, <<io#io.rest-client, rest clients>> and more in this section.

spring-boot-project/spring-boot-docs/src/docs/asciidoc/upgrading.adoc

@@ -12,4 +12,6 @@ include::upgrading/from-1x.adoc[]
 
 include::upgrading/to-feature.adoc[]
 
-include::upgrading/cli.adoc[]
+include::upgrading/cli.adoc[]
+
+include::upgrading/whats-next.adoc[]

spring-boot-project/spring-boot-docs/src/docs/asciidoc/upgrading/whats-next.adoc

@@ -0,0 +1,5 @@
+[[upgrading.whats-next]]
+== What to Read Next
+Once you've decided to upgrade your application, you can find detailed information regarding specific features in the rest of the document.
+
+Spring Boot's documentation is specific to that version, so any information that you find in here will contain the most up-to-date changes that are in that version.

spring-boot-project/spring-boot-docs/src/docs/asciidoc/web.adoc

@@ -20,3 +20,5 @@ include::web/spring-security.adoc[]
 include::web/spring-session.adoc[]
 
 include::web/spring-hateoas.adoc[]
+
+include::web/whats-next.adoc[]

spring-boot-project/spring-boot-docs/src/docs/asciidoc/web/whats-next.adoc

@@ -0,0 +1,5 @@
+[[web.whats-next]]
+== What to Read Next
+You should now have a good understanding of how to develop  web applications with Spring Boot.
+The next few sections describe how Spring Boot integrates with various <<data#data, data technologies>>, <<messaging#messaging, messaging systems>>, and other IO capabilities.
+You can pick any of these based on your application's needs.