Fix posting format for CompletionFieldMapper

Signed-off-by: Andriy Redko <andriy.redko@aiven.io>

Author: reta

server/src/main/java/org/opensearch/index/mapper/CompletionFieldMapper.java

@@ -35,7 +35,7 @@
 import org.apache.lucene.document.FieldType;
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.Term;
-import org.apache.lucene.search.suggest.document.Completion912PostingsFormat;
+import org.apache.lucene.search.suggest.document.Completion101PostingsFormat;
 import org.apache.lucene.search.suggest.document.CompletionAnalyzer;
 import org.apache.lucene.search.suggest.document.CompletionQuery;
 import org.apache.lucene.search.suggest.document.FuzzyCompletionQuery;
@@ -330,7 +330,7 @@ public ContextMappings getContextMappings() {
          */
         public static synchronized PostingsFormat postingsFormat() {
             if (postingsFormat == null) {
-                postingsFormat = new Completion912PostingsFormat();
+                postingsFormat = new Completion101PostingsFormat();
             }
             return postingsFormat;
         }