Fixed back reference link in adapter pages

docs/src/main/asciidoc/adapters/aws.adoc

@@ -1,5 +1,9 @@
 *{spring-cloud-function-version}*
 
+[#index-link]
+{docs-url}spring-cloud-function/{docs-version}home.html
+
+
 The https://aws.amazon.com/[AWS] adapter takes a Spring Cloud Function app and converts it to a form that can run in AWS Lambda.
 
 == Introduction

docs/src/main/asciidoc/adapters/azure.adoc

@@ -1,5 +1,9 @@
 *{spring-cloud-function-version}*
 
+[#index-link]
+{docs-url}spring-cloud-function/{docs-version}home.html
+
+
 The https://azure.microsoft.com[Azure] adapter bootstraps a Spring Cloud Function context and channels function calls from the Azure framework into the user functions, using Spring Boot configuration where necessary. Azure Functions has quite a unique, but invasive programming model, involving annotations in user code that are specific to the platform. The easiest way to use it with Spring Cloud is to extend a base class and write a method in it with the `@FunctionName` annotation which delegates to a base class method.
 
 include::adapters/azure-intro.adoc[]

docs/src/main/asciidoc/adapters/openwhisk.adoc

@@ -1,5 +1,9 @@
 *{spring-cloud-function-version}*
 
+[#index-link]
+{docs-url}spring-cloud-function/{docs-version}home.html
+
+
 The https://openwhisk.apache.org/[OpenWhisk] adapter is in the form of an executable jar that can be used in a a docker image to be deployed to Openwhisk. The platform works in request-response mode, listening on port 8080 on a specific endpoint, so the adapter is a simple Spring MVC application.
 
 == Quick Start