changed error and the wrong comment

Author: mridula-s109

x-pack/plugin/search-business-rules/src/main/java/org/elasticsearch/xpack/searchbusinessrules/retriever/PinnedRetrieverBuilder.java

@@ -157,7 +157,6 @@ public int rankWindowSize() {
 
     /**
      * Creates a PinnedQueryBuilder with the appropriate pinned documents.
-     * Prioritizes docs over ids if both are present.
      *
      * @param baseQuery the base query to pin documents to
      * @return a PinnedQueryBuilder
@@ -177,7 +176,7 @@ protected SearchSourceBuilder finalizeSourceBuilder(SearchSourceBuilder source)
         validateSort(source);
         QueryBuilder underlyingQuery = source.query();
         if (underlyingQuery == null) {
-            throw new IllegalArgumentException("[underlying query] must not be null for pinned retriever");
+            throw new IllegalArgumentException("pinned retriever requires retriever with associated query");
         }
         source.query(createPinnedQuery(underlyingQuery));
         return source;
@@ -216,7 +215,7 @@ protected RankDoc[] combineInnerRetrieverResults(List<ScoreDoc[]> rankResults, b
                 boolean isPinned = scoreDoc.score > PinnedQueryBuilder.MAX_ORGANIC_SCORE;
                 if (isPinned) {
                     String pinnedBy = (this.ids != null && this.ids.isEmpty() == false) ? "ids" : "docs";
-                    rankDocs[i] = new PinnedRankDoc(scoreDoc.doc, scoreDoc.score, scoreDoc.shardIndex, true);
+                    rankDocs[i] = new PinnedRankDoc(scoreDoc.doc, scoreDoc.score, scoreDoc.shardIndex, true, pinnedBy);
                 } else {
                     rankDocs[i] = new RankDoc(scoreDoc.doc, scoreDoc.score, scoreDoc.shardIndex);
                 }