Update relnotes

doc/relnotes/README.md

@@ -20,6 +20,10 @@ evil organizations.
     * Mining now starts faster because instead of only using 2 threads to prepare
       data needed to mine, now it uses all physical cores
   * RandomX mining takes slightly less memory
+  * `ac_sapling` is no longer an option for Arrakis Chains
+    * All chains enable Sapling at height 1 like Hush + DragonX
+    * This means there is no need to call `NetworkUpgradeActive` on every block height
+      which means syncing is faster
   * Update to wolfssl 5.2.0: https://git.hush.is/hush/hush3/issues/380
   * Delete cryptoconditions: https://git.hush.is/hush/hush3/issues/381
     * This means Hush+DragonX full nodes take up a lot less memory and binaries are smaller