docs: update release-notes-0.19.0.md

Update release-notes-0.19.0.md

Author: gap-editor

docs/release-notes/release-notes-0.19.0.md

@@ -526,6 +526,13 @@ selected use postgres for the neutrino.db store](https://github.com/lightningnet
 - [Fixed a few misspellings](https://github.com/lightningnetwork/lnd/pull/9290)
   of "broadcast" in the code base, specifically the `lncli peers updatenodeannouncement`
   command documentation.
+  
+* [Add usage and desc to wtclient session cmd](https://github.com/lightningnetwork/lnd/pull/9765):
+  Enhanced documentation for the `session` and `terminate` commands in
+  `lncli wtclient`. The `session` command now includes a comprehensive
+  explanation of its role in managing watchtower client sessions. The `terminate`
+  command offers clear instructions for ending an active session using its unique
+  session ID.
 
 # Contributors (Alphabetical Order)