doc: Remove release notes of backports

doc/release-notes-19219.md

@@ -1,23 +0,0 @@
-#### Changes regarding misbehaving peers
-
-Peers that misbehave (e.g. send us invalid blocks) are now referred to as
-discouraged nodes in log output, as they're not (and weren't) strictly banned:
-incoming connections are still allowed from them, but they're preferred for
-eviction.
-
-Furthermore, a few additional changes are introduced to how discouraged
-addresses are treated:
-
-- Discouraging an address does not time out automatically after 24 hours
-  (or the `-bantime` setting). Depending on traffic from other peers,
-  discouragement may time out at an indeterminate time.
-
-- Discouragement is not persisted over restarts.
-
-- There is no method to list discouraged addresses. They are not returned by
-  the `listbanned` RPC. That RPC also no longer reports the `ban_reason`
-  field, as `"manually added"` is the only remaining option.
-
-- Discouragement cannot be removed with the `setban remove` RPC command.
-  If you need to remove a discouragement, you can remove all discouragements by
-  stop-starting your node.