Reload KnnVectorsFormat to allow plugins to declare a custom knn vectors format.

Author: ChrisHegarty

server/src/main/java/org/elasticsearch/plugins/PluginsService.java

@@ -13,6 +13,7 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.codecs.Codec;
 import org.apache.lucene.codecs.DocValuesFormat;
+import org.apache.lucene.codecs.KnnVectorsFormat;
 import org.apache.lucene.codecs.PostingsFormat;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.action.admin.cluster.node.info.PluginsAndModules;
@@ -477,6 +478,7 @@ static void reloadLuceneSPI(ClassLoader loader) {
         // Codecs:
         PostingsFormat.reloadPostingsFormats(loader);
         DocValuesFormat.reloadDocValuesFormats(loader);
+        KnnVectorsFormat.reloadKnnVectorsFormat(loader);
         Codec.reloadCodecs(loader);
     }