Update CHANGELOG to mention deprecation of file() for files().

I missed this update in #4334.

Issue: #4122

CHANGELOG.md

@@ -94,8 +94,9 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
   commit to commit. It now either follows the flags `--edit|--no-edit` or it
   gets the mode from `ui.movement.edit`.
 
-* `conflict` revset has been renamed to `conflicts`. With this, all revsets that
-  could potentially return multiple results are named in the plural.
+* `conflict()` and `file()` revsets have been renamed to `conflicts()` and `files()`
+  respectively. With this, all revsets that could potentially return multiple
+  results are named in the plural.
 
 ### Deprecations