docs: add release notes for v1 taproot funding script fix

Author: ellemouton

docs/release-notes/release-notes-0.21.0.md

@@ -56,6 +56,14 @@
   transitions during startup, avoiding lost unlocks during slow database
   initialization.
 
+* [Fixed `FundingPKScript` to honor the taproot feature bit on v1 channel
+  edges](https://github.com/lightningnetwork/lnd/pull/10672). Private taproot
+  channels stored as v1 gossip objects with the taproot staging feature bit
+  were having their funding scripts incorrectly reconstructed as legacy P2WSH
+  multisig. This affected read paths such as `ChannelView`, which rebuilds
+  the chain watch filter on restart. This was a pre-existing bug since
+  private taproot channels were first introduced.
+
 # New Features
 
 - [Basic Support](https://github.com/lightningnetwork/lnd/pull/9868) for onion