db::hints: manager.hh: cleanup: fix the comments
db::hints: manager.hh: cleanup: fix the comments

Fix the comments that went out of sync with the current implementation.

Signed-off-by: Vlad Zolotarov <976c0f8d0852ed6439ad273880b400a75a7c41d0@scylladb.com>

duarten/scylla,avikivity/scylla,avikivity/scylla,avikivity/scylla,duarten/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla,duarten/scylla