Update docs/changelog.md

Author: saulshanabrook

docs/changelog.md

@@ -5,7 +5,6 @@ _This project uses semantic versioning_
 ## UNRELEASED
 
 - Automatically Create Changelog Entry for PRs [#313](https://github.com/egraphs-good/egglog-python/pull/313)
-- Automatically Generate Changelog Entries for PRs [#312](https://github.com/egraphs-good/egglog-python/pull/312)
 - Upgrade egglog which includes new backend.
   - Fixes implementation of the Python Object sort to work with objects with dupliating hashes but the same value.
     Also changes the representation to be an index into a list instead of the ID, making egglog programs more deterministic.