Remove DrillSideways#createDrillDownFacetsCollector in favor of the manager-based hook (#12855)

lucene/CHANGES.txt

@@ -75,6 +75,8 @@ API Changes
   (allows handling long fields with lots of hits more gracefully). MatchRegionRetriever utilizes IndexSearcher's
   executor to extract hit offsets concurrently. (Dawid Weiss)
 
+* GITHUB#12855: Remove deprecated DrillSideways#createDrillDownFacetsCollector extension method. (Greg Miller)
+
 New Features
 ---------------------
 
@@ -165,6 +167,8 @@ API Changes
   IndexSearcher#search(Query, CollectorManager) for TopFieldCollectorManager
   and TopScoreDocCollectorManager. (Zach Chen, Adrien Grand, Michael McCandless, Greg Miller, Luca Cavanna)
 
+* GITHUB#12854: Mark DrillSideways#createDrillDownFacetsCollector as @Deprecated. (Greg Miller)
+
 New Features
 ---------------------
 (No changes)

lucene/facet/src/java/org/apache/lucene/facet/DrillSideways.java

@@ -129,14 +129,6 @@ public class DrillSideways {
     this.executor = executor;
   }
 
-  /**
-   * Subclass can override to customize drill down facets collector. Returning {@code null} is valid
-   * if no drill down facet collection is needed.
-   */
-  protected FacetsCollector createDrillDownFacetsCollector() {
-    return new FacetsCollector();
-  }
-
   /**
    * Subclass can override to customize drill down facets collector. Returning {@code null} is valid
    * if no drill down facet collection is needed.

lucene/facet/src/test/org/apache/lucene/facet/TestDrillSideways.java

@@ -1983,11 +1983,6 @@ public class TestDrillSideways extends FacetTestCase {
     // Don't collect for drill down faceting
     DrillSideways ds =
         new DrillSideways(searcher, config, taxoReader, null, executorService) {
-          @Override
-          protected FacetsCollector createDrillDownFacetsCollector() {
-            return null;
-          }
-
           @Override
           protected FacetsCollectorManager createDrillDownFacetsCollectorManager() {
             return null;