Improve javadoc in RollbackRuleAttribute regarding nested classes

Closes gh-24682

Co-authored-by: Sam Brannen <sbrannen@pivotal.io>

spring-tx/src/main/java/org/springframework/transaction/interceptor/RollbackRuleAttribute.java

@@ -54,7 +54,7 @@ public class RollbackRuleAttribute implements Serializable{
 	/**
 	 * Create a new instance of the {@code RollbackRuleAttribute} class.
 	 * <p>This is the preferred way to construct a rollback rule that matches
-	 * the supplied {@link Exception} class (and subclasses).
+	 * the supplied {@link Exception} class, its subclasses, and its nested classes.
 	 * @param clazz throwable class; must be {@link Throwable} or a subclass
 	 * of {@code Throwable}
 	 * @throws IllegalArgumentException if the supplied {@code clazz} is

spring-tx/src/test/java/org/springframework/transaction/interceptor/RollbackRuleTests.java

@@ -88,4 +88,19 @@ public class RollbackRuleTests {
 				new RollbackRuleAttribute((String) null));
 	}
 
+	@Test
+	public void foundEnclosedExceptionWithEnclosingException() {
+		RollbackRuleAttribute rr = new RollbackRuleAttribute(EnclosingException.class);
+		assertThat(rr.getDepth(new EnclosingException.EnclosedException())).isEqualTo(0);
+	}
+
+	@SuppressWarnings("serial")
+	static class EnclosingException extends RuntimeException {
+
+		@SuppressWarnings("serial")
+		static class EnclosedException extends RuntimeException {
+
+		}
+	}
+
 }