Fix old changelog formatting errors

Author: nightkr

crates/stackable-operator/CHANGELOG.md

@@ -74,7 +74,6 @@ All notable changes to this project will be documented in this file.
 
 [#821]: https://github.com/stackabletech/operator-rs/pull/821
 [#827]: https://github.com/stackabletech/operator-rs/pull/827
-[#840]: https://github.com/stackabletech/operator-rs/pull/840
 
 ## [0.71.0] - 2024-07-29
 
@@ -518,9 +517,6 @@ Only rust documentation was changed.
 - `PodListeners` CRD ([#644]).
 - Add support for tls pkcs12 password to secret operator volume builder ([#645]).
 
-[#644]: https://github.com/stackabletech/operator-rs/pull/644
-[#645]: https://github.com/stackabletech/operator-rs/pull/645
-
 ### Changed
 
 - Derive `Eq` and `Copy` where applicable for listener CRDs ([#644]).
@@ -1187,7 +1183,7 @@ This is a rerelease of 0.25.1 which some last-minute incompatible API changes to
 
 ### Changed
 
-- BREAKING: kube 0.68 -> 0.69.1 ([#319, [#322]]).
+- BREAKING: kube 0.68 -> 0.69.1 ([#319], [#322]).
 
 ### Removed