Docs/admin-guide/mm/damon/usage: fix wrong example of DAMOS filter matching sysfs file

The example usage of DAMOS filter sysfs files, specifically the part of
'matching' file writing for memcg type filter, is wrong.  The intention is
to exclude pages of a memcg that already getting enough care from a given
scheme, but the example is setting the filter to apply the scheme to only
the pages of the memcg.  Fix it.

Link: https://lkml.kernel.org/r/20240503180318.72798-7-sj@kernel.org
Fixes: 9b7f932 ("Docs/admin-guide/mm/damon/usage: document DAMOS filters of sysfs")
Closes: https://lore.kernel.org/r/20240317191358.97578-1-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[6.3.x]
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: sjp38

Documentation/admin-guide/mm/damon/usage.rst

@@ -434,7 +434,7 @@ pages of all memory cgroups except ``/having_care_already``.::
     # # further filter out all cgroups except one at '/having_care_already'
     echo memcg > 1/type
     echo /having_care_already > 1/memcg_path
-    echo N > 1/matching
+    echo Y > 1/matching
 
 Note that ``anon`` and ``memcg`` filters are currently supported only when
 ``paddr`` :ref:`implementation <sysfs_context>` is being used.