docs: notifier-error-inject: Correct test's name

Correct test's name for mem-on-off-test.sh/cpu-on-off-test.sh.
Signed-off-by: Zhao Gongyi <zhaogongyi@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Documentation/fault-injection/notifier-error-inject.rst

@@ -91,8 +91,8 @@ For more usage examples
 There are tools/testing/selftests using the notifier error injection features
 for CPU and memory notifiers.
 
- * tools/testing/selftests/cpu-hotplug/on-off-test.sh
- * tools/testing/selftests/memory-hotplug/on-off-test.sh
+ * tools/testing/selftests/cpu-hotplug/cpu-on-off-test.sh
+ * tools/testing/selftests/memory-hotplug/mem-on-off-test.sh
 
 These scripts first do simple online and offline tests and then do fault
 injection tests if notifier error injection module is available.