Fix Javadoc references to incorrect XML

Replace references to <task:annotation-config> with
<task:annotation-driven>

spring-context/src/main/java/org/springframework/scheduling/annotation/EnableAsync.java

@@ -88,7 +88,7 @@ import org.springframework.core.Ordered;
  * <pre class="code">
  * {@code
  * <beans>
- *     <task:annotation-config executor="myExecutor"/>
+ *     <task:annotation-driven executor="myExecutor"/>
  *     <task:executor id="myExecutor" pool-size="7-42" queue-capacity="11"/>
  *     <bean id="asyncBean" class="com.foo.MyAsyncBean"/>
  * </beans>

spring-context/src/main/java/org/springframework/scheduling/annotation/EnableScheduling.java

@@ -153,7 +153,7 @@ import org.springframework.scheduling.config.ScheduledTaskRegistrar;
  * <pre class="code">
  * {@code
  * <beans>
- *     <task:annotation-config scheduler="taskScheduler"/>
+ *     <task:annotation-driven scheduler="taskScheduler"/>
  *     <task:scheduler id="taskScheduler" pool-size="42"/>
  *     <task:scheduled ref="myTask" method="work" fixed-rate="1000"/>
  *     <bean id="myTask" class="com.foo.MyTask"/>