Add offending type name to AbstractRepositoryMetadata verification exception message.

Closes #3091

Author: kgignatyev

src/main/java/org/springframework/data/repository/core/support/AbstractRepositoryMetadata.java

@@ -41,6 +41,7 @@
  * @author Thomas Darimont
  * @author Jens Schauder
  * @author Mark Paluch
+ * @author Konstntin Ignatyev
  */
 public abstract class AbstractRepositoryMetadata implements RepositoryMetadata {
 
@@ -56,7 +57,7 @@ public abstract class AbstractRepositoryMetadata implements RepositoryMetadata {
 	public AbstractRepositoryMetadata(Class<?> repositoryInterface) {
 
 		Assert.notNull(repositoryInterface, "Given type must not be null");
-		Assert.isTrue(repositoryInterface.isInterface(), "Given type must be an interface");
+		Assert.isTrue(repositoryInterface.isInterface(), "Given type ["+ repositoryInterface.getName()+"] must be an interface");
 
 		this.repositoryInterface = repositoryInterface;
 		this.typeInformation = TypeInformation.of(repositoryInterface);