[minor][docs][style] Update documentation link and improve code style (apache#3961)

Author: jinkachy

flink-cdc-connect/flink-cdc-pipeline-connectors/flink-cdc-pipeline-connector-elasticsearch/src/main/java/org/apache/flink/cdc/connectors/elasticsearch/sink/ElasticsearchDataSinkFactory.java

@@ -73,7 +73,7 @@ public DataSink createDataSink(Context context) {
 
         ZoneId zoneId = determineZoneId(context);
         ElasticsearchSinkOptions sinkOptions = buildSinkConnectorOptions(configuration);
-        return new ElasticsearchDataSink(sinkOptions, zoneId);
+        return new ElasticsearchDataSink<>(sinkOptions, zoneId);
     }
 
     private ZoneId determineZoneId(Context context) {

flink-cdc-connect/flink-cdc-pipeline-connectors/flink-cdc-pipeline-connector-mysql/src/main/java/org/apache/flink/cdc/connectors/mysql/source/MySqlEventDeserializer.java

@@ -70,8 +70,8 @@ public class MySqlEventDeserializer extends DebeziumEventDeserializationSchema {
     private transient Tables tables;
     private transient CustomMySqlAntlrDdlParser customParser;
 
-    private List<MySqlReadableMetadata> readableMetadataList;
-    private boolean isTableIdCaseInsensitive;
+    private final List<MySqlReadableMetadata> readableMetadataList;
+    private final boolean isTableIdCaseInsensitive;
 
     public MySqlEventDeserializer(
             DebeziumChangelogMode changelogMode,
@@ -85,7 +85,6 @@ public MySqlEventDeserializer(
                 includeSchemaChanges,
                 tinyInt1isBit,
                 isTableIdCaseInsensitive);
-        this.isTableIdCaseInsensitive = isTableIdCaseInsensitive;
     }
 
     public MySqlEventDeserializer(

flink-cdc-connect/flink-cdc-pipeline-connectors/flink-cdc-pipeline-connector-starrocks/src/main/java/org/apache/flink/cdc/connectors/starrocks/sink/StarRocksDataSinkOptions.java

@@ -136,8 +136,8 @@ public class StarRocksDataSinkOptions {
 
     /**
      * The prefix for properties used for creating a table. You can refer to StarRocks documentation
-     * for the DDL.
-     * https://docs.starrocks.io/docs/table_design/table_types/primary_key_table/#create-a-table
+     * for the DDL. <a
+     * href="https://docs.starrocks.io/docs/table_design/table_types/primary_key_table/#create-primary-key-table">create-primary-key-table</a>
      */
     public static final String TABLE_CREATE_PROPERTIES_PREFIX = "table.create.properties.";