docs: update release notes

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

@@ -48,6 +48,9 @@
 * [Fixed a bug](https://github.com/lightningnetwork/lnd/pull/9249) found in the
   mission control store that can block the shutdown process of LND.
 
+* Make sure the RPC clients used to access the chain backend are [properly
+  shutdown](https://github.com/lightningnetwork/lnd/pull/9261).
+
 # New Features
 ## Functional Enhancements
 ## RPC Additions
@@ -196,4 +199,5 @@ The underlying functionality between those two options remain the same.
 * Oliver Gugger
 * Pins
 * Viktor Tigerström
-* Ziggie
+* Ziggie
+