docs: add release notes for 19.1

Author: ziggie1984

docs/release-notes/release-notes-0.19.1.md

@@ -20,7 +20,7 @@
 
 # Bug Fixes
 
-* [Fix a serialisation bug](https://github.com/lightningnetwork/lnd/pull/9856) 
+- [Fix a serialisation bug](https://github.com/lightningnetwork/lnd/pull/9856) 
   that would occur when an attempt was made to write a backup file for a channel 
   peer that has advertised an address that we do not yet know how to parse. 
 
@@ -38,6 +38,9 @@
 
 ## Functional Enhancements
 
+- [Increase](https://github.com/lightningnetwork/lnd/pull/9875) gossip sync
+  buffer to take the pressure of the read handler.
+
 ## RPC Additions
 
 ## lncli Additions