simplify configuration for Antora Collector (#12152)

- use shortform value when applicable
- rename base key to into

documentation/jetty/antora.yml

@@ -17,11 +17,9 @@ nav:
 - modules/programming-guide/nav.adoc
 ext:
   collector:
-  - run:
-      command: mvn install -ntp -B -Dcollector -Pfast -am -pl documentation/jetty
-    scan:
-      dir: documentation/jetty/target/collector
+  - run: mvn install -ntp -B -Dcollector -Pfast -am -pl documentation/jetty
+    scan: ./target/collector
   - scan:
       dir: jetty-core/jetty-server/src/main/java
       files: org/eclipse/jetty/server/CustomRequestLog.java
-      base: modules/code/partials
+      into: modules/code/partials