Fix ArtifactArchiver javadoc: patterns must be comma-separated (#27557)

Fix ArtifactArchiver javadoc to say comma-separated patterns

Whitespace is no longer accepted as a pattern separator: FilePath
validation rejects it with an explicit error message. The field
javadoc still described the list as comma- or space-separated, and the
excludes javadoc pointed at Ant semantics without noting the stricter
separator. Align the javadoc with the enforced behavior.

core/src/main/java/hudson/tasks/ArtifactArchiver.java

@@ -77,12 +77,12 @@ public class ArtifactArchiver extends Recorder implements SimpleBuildStep {
     private static final Logger LOG = Logger.getLogger(ArtifactArchiver.class.getName());
 
     /**
-     * Comma- or space-separated list of patterns of files/directories to be archived.
+     * Comma-separated list of patterns of files/directories to be archived.
      */
     private String artifacts;
 
     /**
-     * Possibly null 'excludes' pattern as in Ant.
+     * Possibly null comma-separated 'excludes' pattern, using Ant-style wildcards.
      */
     private String excludes;