docs/recovery: add Last resort manual force close

Also updated release-notes.

docs/recovery.md

@@ -258,6 +258,22 @@ An example of using file system level notification to [copy the backup to a
 distinct volume/partition/drive can be found
 here](https://gist.github.com/alexbosworth/2c5e185aedbdac45a03655b709e255a3).
 
+##### Last resort manual force close
+
+Reserve this option as a last resort when the peer is offline and all other
+avenues to retrieve funds from the channel have been exhausted. The primary
+motivation for introducing this option is to provide a means of recovery,
+albeit with some risk, rather than losing the funds indefinitely. This is a very
+dangerous option, so it should only be used after consulting with a recovery
+specialist or after opening an issue to make sure!!!
+
+Starting with release 0.18.3 LND includes unsigned force close transaction
+for a channel into channel.backup file and RPCs returning channel backups.
+To generate a force close transaction from the backup file, utilize the
+`chantools scbforceclose` command. However, exercise caution as this action is
+perilous. If the channel has been updated since the backup creation, another
+node or a watchtower may issue a penalty transaction, seizing all funds!
+
 #### Using the `ExportChanBackup` RPC
 
 Another way to obtain SCBS for all or a target channel is via the new

docs/release-notes/release-notes-0.18.3.md

@@ -51,6 +51,13 @@
 
 # Improvements
 ## Functional Updates
+
+* The SCB file now [contains more data][https://github.com/lightningnetwork/lnd/pull/8183]
+  that enable a last resort rescue for certain cases where the peer is no longer
+  around.
+
+* LND updates channel.backup file at shutdown time.
+
 ## RPC Updates
 
 * [`xImportMissionControl`](https://github.com/lightningnetwork/lnd/pull/8779) 
@@ -63,7 +70,7 @@
 
 * [`importmc`](https://github.com/lightningnetwork/lnd/pull/8779) now accepts
   `0` failure amounts.
- 
+
 * [`getchaninfo`](https://github.com/lightningnetwork/lnd/pull/8813) now accepts
   a channel outpoint besides a channel id.
 
@@ -115,6 +122,7 @@
 # Contributors (Alphabetical Order)
 
 * Andras Banki-Horvath
+* Boris Nagaev
 * Bufo
 * Elle Mouton
 * Matheus Degiovani