GH-713 - Create aggregating Asciidoc document including all files generated.

src/docs/antora/modules/ROOT/pages/documentation.adoc

@@ -7,6 +7,8 @@ Spring Modulith's `Documenter` abstraction can produce two different kinds of sn
 * C4 and UML component diagrams describing the relationships between the individual application modules
 * A so-called __Application Module Canvas__, a tabular overview about the module and the most relevant elements in those (Spring beans, aggregate roots, events published and listened to as well as configuration properties).
 
+Additionally, `Documenter` can produce an aggregating Asciidoc file that includes all existing component diagrams and canvases.
+
 [[component-diagrams]]
 == Generating Application Module Component diagrams
 
@@ -302,3 +304,46 @@ This will detect component stereotypes defined by https://github.com/xmolecules/
 * __Application events listened to by the module__ -- Derived from methods annotated with Spring's `@EventListener`, `@TransactionalEventListener`, jMolecules' `@DomainEventHandler` or beans implementing `ApplicationListener`.
 * __Configuration properties__ -- Spring Boot Configuration properties exposed by the application module.
 Requires the usage of the `spring-boot-configuration-processor` artifact to extract the metadata attached to the properties.
+
+[[aggregating-document]]
+== Generating an Aggregating Document
+
+The aggregating document can be generated by calling `Documenter.writeAggregatingDocument()`:
+
+.Generating an aggregating document using `Documenter`
+[tabs]
+======
+Java::
++
+[source, java, role="primary"]
+----
+class DocumentationTests {
+
+  ApplicationModules modules = ApplicationModules.of(Application.class);
+
+  @Test
+  void writeDocumentationSnippets() {
+
+    new Documenter(modules)
+      .writeAggregatingDocument();
+  }
+}
+----
+Kotlin::
++
+[source, kotlin, role="secondary"]
+----
+class DocumentationTests {
+
+  private val modules = ApplicationModules.of(Application::class)
+
+  @Test
+  fun writeDocumentationSnippets() {
+    Documenter(modules)
+        .writeAggregatingDocument()
+  }
+}
+----
+======
+
+The aggregating document will include any existing application module component diagrams and application module canvases. If there are none, then this method will not produce an output file.