Fix JDK 21 lint warnings (elastic#112249)

This commit fixes lint warnings that arise when compiling with javac from JDK 21.

This change is in preparation for an eventual bump of Elasticsearch to a minimum of JDK 21, in ES 9.0.

Author: ChrisHegarty

server/src/main/java/org/elasticsearch/action/admin/cluster/allocation/TransportGetAllocationStatsAction.java

@@ -108,6 +108,7 @@ public static class Request extends MasterNodeReadRequest<Request> {
 
         private final EnumSet<Metric> metrics;
 
+        @SuppressWarnings("this-escape")
         public Request(TimeValue masterNodeTimeout, TaskId parentTaskId, EnumSet<Metric> metrics) {
             super(masterNodeTimeout);
             setParentTask(parentTaskId);

server/src/main/java/org/elasticsearch/action/admin/indices/resolve/ResolveClusterActionRequest.java

@@ -54,12 +54,14 @@ public ResolveClusterActionRequest(String[] names) {
         this(names, DEFAULT_INDICES_OPTIONS);
     }
 
+    @SuppressWarnings("this-escape")
     public ResolveClusterActionRequest(String[] names, IndicesOptions indicesOptions) {
         this.names = names;
         this.localIndicesRequested = localIndicesPresent(names);
         this.indicesOptions = indicesOptions;
     }
 
+    @SuppressWarnings("this-escape")
     public ResolveClusterActionRequest(StreamInput in) throws IOException {
         super(in);
         if (in.getTransportVersion().before(TransportVersions.V_8_13_0)) {

server/src/main/java/org/elasticsearch/action/delete/DeleteRequestBuilder.java

@@ -30,6 +30,7 @@ public class DeleteRequestBuilder extends ReplicationRequestBuilder<DeleteReques
     private Long term;
     private WriteRequest.RefreshPolicy refreshPolicy;
 
+    @SuppressWarnings("this-escape")
     public DeleteRequestBuilder(ElasticsearchClient client, @Nullable String index) {
         super(client, TransportDeleteAction.TYPE);
         setIndex(index);

server/src/main/java/org/elasticsearch/action/index/IndexRequestBuilder.java

@@ -54,6 +54,7 @@ public IndexRequestBuilder(ElasticsearchClient client) {
         this(client, null);
     }
 
+    @SuppressWarnings("this-escape")
     public IndexRequestBuilder(ElasticsearchClient client, @Nullable String index) {
         super(client, TransportIndexAction.TYPE);
         setIndex(index);

server/src/main/java/org/elasticsearch/action/update/UpdateRequestBuilder.java

@@ -68,6 +68,7 @@ public UpdateRequestBuilder(ElasticsearchClient client) {
         this(client, null, null);
     }
 
+    @SuppressWarnings("this-escape")
     public UpdateRequestBuilder(ElasticsearchClient client, String index, String id) {
         super(client, TransportUpdateAction.TYPE);
         setIndex(index);

server/src/main/java/org/elasticsearch/client/internal/support/AbstractClient.java

@@ -93,6 +93,7 @@ public abstract class AbstractClient implements Client {
     private final ThreadPool threadPool;
     private final AdminClient admin;
 
+    @SuppressWarnings("this-escape")
     public AbstractClient(Settings settings, ThreadPool threadPool) {
         this.settings = settings;
         this.threadPool = threadPool;

server/src/main/java/org/elasticsearch/index/codec/CodecService.java

@@ -97,6 +97,7 @@ public static class DeduplicateFieldInfosCodec extends FilterCodec {
 
         private final DeduplicatingFieldInfosFormat deduplicatingFieldInfosFormat;
 
+        @SuppressWarnings("this-escape")
         protected DeduplicateFieldInfosCodec(String name, Codec delegate) {
             super(name, delegate);
             this.deduplicatingFieldInfosFormat = new DeduplicatingFieldInfosFormat(super.fieldInfosFormat());

server/src/main/java/org/elasticsearch/index/mapper/Mapper.java

@@ -26,6 +26,7 @@ public abstract static class Builder {
 
         private String leafName;
 
+        @SuppressWarnings("this-escape")
         protected Builder(String leafName) {
             setLeafName(leafName);
         }
@@ -55,6 +56,7 @@ default boolean supportsVersion(IndexVersion indexCreatedVersion) {
 
     private final String leafName;
 
+    @SuppressWarnings("this-escape")
     public Mapper(String leafName) {
         Objects.requireNonNull(leafName);
         this.leafName = internFieldName(leafName);

server/src/main/java/org/elasticsearch/index/reindex/DeleteByQueryRequestBuilder.java

@@ -20,6 +20,7 @@ public DeleteByQueryRequestBuilder(ElasticsearchClient client) {
         this(client, new SearchRequestBuilder(client));
     }
 
+    @SuppressWarnings("this-escape")
     private DeleteByQueryRequestBuilder(ElasticsearchClient client, SearchRequestBuilder search) {
         super(client, DeleteByQueryAction.INSTANCE, search);
         source().setFetchSource(false);

server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalStats.java

@@ -56,6 +56,7 @@ public static boolean hasMetric(String name) {
     protected final double max;
     protected final double sum;
 
+    @SuppressWarnings("this-escape")
     public InternalStats(
         String name,
         long count,