Add some release notes

doc/relnotes/README.md

@@ -10,6 +10,15 @@ and no longer on Github, since they banned Duke Leto and
 also because they censor many people around the world and work with
 evil organizations.
 
+# Hush 3.9.1 ""
+
+This is an OPTIONAL release.
+
+  * The `listbanned` RPC now returns a new key `time_remaining` which tells how many
+    seconds are remaining in the ban
+  * The `rescan` RPC now works correctly when given a height. This can be used to do
+    a partial rescan from a custom height, without restarting the node.
+
 # Hush 3.9.0 "Unusual Ursid"
 ```
  136 files changed, 3881 insertions(+), 3156 deletions(-)