Docs/ABI/damon: update for 'youg page' type DAMOS filter

Update DAMON ABI document for the newly added DAMO filter type, 'young
page'.

Link: https://lkml.kernel.org/r/20240426195247.100306-8-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/ABI/testing/sysfs-kernel-mm-damon

@@ -314,9 +314,9 @@ Date:		Dec 2022
 Contact:	SeongJae Park <sj@kernel.org>
 Description:	Writing to and reading from this file sets and gets the type of
 		the memory of the interest.  'anon' for anonymous pages,
-		'memcg' for specific memory cgroup, 'addr' for address range
-		(an open-ended interval), or 'target' for DAMON monitoring
-		target can be written and read.
+		'memcg' for specific memory cgroup, 'young' for young pages,
+		'addr' for address range (an open-ended interval), or 'target'
+		for DAMON monitoring target can be written and read.
 
 What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/memcg_path
 Date:		Dec 2022