Docs/ABI/damon: update for DAMON monitoring target type DAMOS filter

Update DAMON ABI document for the newly added DAMON monitoring target type
DAMOS filter.

Link: https://lkml.kernel.org/r/20230802214312.110532-13-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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

@@ -272,8 +272,9 @@ 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, or 'addr' for address range
-		(an open-ended interval) can be written and read.
+		'memcg' for specific memory cgroup, '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
@@ -296,6 +297,12 @@ Description:	If 'addr' is written to the 'type' file, writing to or reading
 		from this file sets or gets the end address of the address
 		range for the filter.
 
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/target_idx
+Date:		Dec 2022
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	If 'target' is written to the 'type' file, writing to or
+		reading from this file sets or gets the index of the DAMON
+		monitoring target of the interest.
 
 What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/filters/<F>/matching
 Date:		Dec 2022