fixes changelog for oids (#20565)

Author: ringabout

changelog.md

@@ -108,8 +108,7 @@
   making limiting it to just the first char (`last = 0`) valid.
 - `random.rand` now works with `Ordinal`s.
 - Undeprecated `os.isvalidfilename`.
-- `std/oids` now uses `int64` to store time internally (before it was int32), the length of
-  the string form of `Oid` changes from 24 to 32.
+- `std/oids` now uses `int64` to store time internally (before it was int32).
 
 [//]: # "Additions:"
 - Added ISO 8601 week date utilities in `times`: