minor refactor: fix asciidoc link

Author: paulk-asert

src/spec/doc/core-async-await.adoc

@@ -264,7 +264,7 @@ loop works identically.
 
 The JDK's `Flow.Publisher` is supported out of the box — no adapter module
 needed. This means streams exposed by built-in sources such as
-`Agent.changes()` (see xref:actors-agent[]) and `BroadcastChannel.asPublisher()`
+`Agent.changes()` (see <<{core-concurrent-actors}#actors-agent,Agent>>) and `BroadcastChannel.asPublisher()`
 (see xref:async-broadcast-channel[]), or any third-party publisher using the JDK
 interfaces, compose directly with `for await` and `await`:
 

subprojects/groovy-binary/src/spec/doc/index.adoc

@@ -43,6 +43,7 @@ include::../../../../../src/spec/doc/core-introduction.adoc[]
 
 == Groovy Language Specification
 
+:core-concurrent-actors:
 :core-domain-specific-languages:
 :core-metaprogramming:
 :core-object-orientation: