Docs/ABI/damon: mark schemes/<S>/filters/ deprecated

Docs/ABI/damon: mark schemes/<S>/filters/ deprecated

Now the 'filters/' directory is deprecated.  Update ABI document to also
announce the fact.  Also update the descriptions of the files to be based
on 'core_filter/' directory, to make the old descriptions ready to be
removed when the time arrives.

Link: https://lore.kernel.org/20260429150309.82282-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>