Fix changelog typos (#494)

Author: AlexWaygood

CHANGELOG.md

@@ -23,8 +23,8 @@ aliases that have a `Concatenate` special form as their argument.
   `Ellipsis` as an argument. Patch by [Daraan](https://github.com/Daraan).
 - Fix error in subscription of `Unpack` aliases causing nested Unpacks 
   to not be resolved correctly. Patch by [Daraan](https://github.com/Daraan).
-- Backport of CPython PR [#124795](https://github.com/python/cpython/pull/124795)
-  and fix that `TypeAliasType` not raising an error on non-tupple inputs for `type_params`.
+- Backport CPython PR [#124795](https://github.com/python/cpython/pull/124795):
+  fix `TypeAliasType` not raising an error on non-tuple inputs for `type_params`.
   Patch by [Daraan](https://github.com/Daraan).
 
 # Release 4.12.2 (June 7, 2024)