Prepare for removal of `ListenableFuture`.

Closes #3190

src/main/java/org/springframework/data/repository/util/QueryExecutionConverters.java

@@ -74,6 +74,7 @@ import org.springframework.util.concurrent.ListenableFuture;
  * @since 1.8
  * @see NullableWrapperConverters
  */
+@SuppressWarnings("removal")
 public abstract class QueryExecutionConverters {
 
 	private static final boolean VAVR_PRESENT = ClassUtils.isPresent("io.vavr.control.Try",
@@ -361,7 +362,8 @@ public abstract class QueryExecutionConverters {
 	 *
 	 * @author Oliver Gierke
 	 */
-	@Deprecated(since = "3.0")
+	@Deprecated(since = "3.0", forRemoval = true)
+	@SuppressWarnings("removal")
 	private static class NullableWrapperToFutureConverter extends AbstractWrapperTypeConverter {
 
 		/**

src/test/java/org/springframework/data/repository/core/support/RepositoryFactorySupportUnitTests.java

@@ -606,6 +606,7 @@ class RepositoryFactorySupportUnitTests {
 
 	}
 
+	@SuppressWarnings("removal")
 	interface ConvertingRepository extends Repository<Object, Long> {
 
 		Set<String> convertListToStringSet();

src/test/java/org/springframework/data/repository/util/QueryExecutionConvertersUnitTests.java

@@ -57,6 +57,7 @@ import com.google.common.base.Optional;
  * @author Maciek Opała
  * @author Johannes Englmeier
  */
+@SuppressWarnings("removal")
 class QueryExecutionConvertersUnitTests {
 
 	DefaultConversionService conversionService;

src/test/java/org/springframework/data/util/NullableWrapperConvertersUnitTests.java

@@ -36,6 +36,7 @@ import com.google.common.base.Optional;
  * @author Mark Paluch
  * @author Maciek Opała
  */
+@SuppressWarnings("removal")
 class NullableWrapperConvertersUnitTests {
 
 	DefaultConversionService conversionService;