Fix link for functions-support.adoc

* Mention `Spring Functions Catalog` project in the `functions-support.adoc`

src/reference/antora/modules/ROOT/nav.adoc

@@ -60,7 +60,7 @@
 *** xref:handler-advice/advised-properties.adoc[]
 *** xref:handler-advice/idempotent-receiver.adoc[]
 ** xref:logging-adapter.adoc[]
-*** xref:functions-support.adoc[]
+** xref:functions-support.adoc[]
 ** xref:kotlin-functions.adoc[]
 * xref:dsl.adoc[]
 ** xref:dsl/java-basics.adoc[]

src/reference/antora/modules/ROOT/pages/changes-5.0-5.1.adoc

@@ -17,7 +17,7 @@ See xref:amqp/strict-ordering.adoc[Strict Message Ordering].
 === Improved Function Support
 
 The `java.util.function` interfaces now have improved integration support in the Framework components.
-Also Kotlin lambdas now can be used for handler and source methods.
+Also, Kotlin lambdas now can be used for handler and source methods.
 
 See xref:functions-support.adoc[`java.util.function` Interfaces Support].
 

src/reference/antora/modules/ROOT/pages/functions-support.adoc

@@ -98,3 +98,5 @@ public IntegrationFlow supplierFlow() {
 ----
 
 This function support is useful when used together with the https://cloud.spring.io/spring-cloud-function/[Spring Cloud Function] framework, where we have a function catalog and can refer to its member functions from an integration flow definition.
+
+Also, many Spring Integration channel adapters and patterns are implemented as functions auto-configuration in https://github.com/spring-cloud/spring-functions-catalog[Spring Functions Catalog] project.