Minor layout refactoring of index asciidoc page

Closes spring-projectsgh-27015

src/docs/asciidoc/index.adoc

@@ -1,19 +1,5 @@
 = Spring Framework Documentation
 
-****
-_What's New_, _Upgrade Notes_, _Supported Versions_, and other topics,
-independent of release cadence, are maintained externally on the project's
-https://github.com/spring-projects/spring-framework/wiki[*Github Wiki*].
-****
-
-ifdef::backend-html5[]
-NOTE: This documentation is also available as {doc-root}/spring-framework/docs/{spring-version}/reference/pdf/index.pdf[PDF].
-endif::[]
-
-ifdef::backend-pdf[]
-NOTE: This documentation is also available as {doc-root}/spring-framework/docs/{spring-version}/reference/html/index.html[HTML].
-endif::[]
-
 [horizontal]
 <<overview.adoc#overview, Overview>> :: history, design philosophy, feedback,
 getting started.
@@ -30,7 +16,17 @@ WebSocket, RSocket.
 <<integration.adoc#spring-integration, Integration>> :: Remoting, JMS, JCA, JMX,
 Email, Tasks, Scheduling, Caching.
 <<languages.adoc#languages, Languages>> :: Kotlin, Groovy, Dynamic Languages.
-<<appendix.adoc#appendix, Appendix>> :: miscellaneous topics.
+<<appendix.adoc#appendix, Appendix>> :: Spring properties.
+https://github.com/spring-projects/spring-framework/wiki[*Wiki*] :: What's New, Upgrade Notes, Supported Versions,
+and other cross-version information.
+
+ifdef::backend-html5[]
+NOTE: This documentation is also available as {doc-root}/spring-framework/docs/{spring-version}/reference/pdf/index.pdf[PDF].
+endif::[]
+
+ifdef::backend-pdf[]
+NOTE: This documentation is also available as {doc-root}/spring-framework/docs/{spring-version}/reference/html/index.html[HTML].
+endif::[]
 
 Rod Johnson, Juergen Hoeller, Keith Donald, Colin Sampaleanu, Rob Harrop, Thomas Risberg,
 Alef Arendsen, Darren Davison, Dmitriy Kopylenko, Mark Pollack, Thierry Templier, Erwin