Make release notes match docu

Author: JungPhilipp

clang-tools-extra/docs/ReleaseNotes.rst

@@ -139,7 +139,8 @@ New checks
 - New :doc:`cppcoreguidelines-use-enum-class
   <clang-tidy/checks/cppcoreguidelines/use-enum-class>` check.
 
-  Finds plain non-class ``enum`` definitions that could use ``enum class``.
+  Finds unscoped (non-class) ``enum`` declarations and suggests using
+  ``enum class`` instead.
 
 - New :doc:`portability-avoid-pragma-once
   <clang-tidy/checks/portability/avoid-pragma-once>` check.