[clang][NFC] add release note for n3030 support (#115648)

Follow-up to #107260

CC @Fznamznon @AaronBallman

Author: h-vetinari

clang/docs/ReleaseNotes.rst

@@ -278,7 +278,7 @@ C2y Feature Support
   which adds the ``i`` and ``j`` suffixes for the creation of a ``_Complex``
   constant value. Clang has always supported these suffixes as a GNU extension,
   so ``-Wgnu-imaginary-constant`` no longer has effect in C modes, as this is
-  not a C2y extension in C. ``-Wgnu-imaginary-constant`` still applies in C++
+  now a C2y extension in C. ``-Wgnu-imaginary-constant`` still applies in C++
   modes.
 
 - Clang updated conformance for `N3370 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3370.htm>`_
@@ -318,6 +318,7 @@ C23 Feature Support
 ^^^^^^^^^^^^^^^^^^^
 
 - Clang now supports `N3029 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3029.htm>`_ Improved Normal Enumerations.
+- Clang now officially supports `N3030 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3030.htm>`_ Enhancements to Enumerations. Clang already supported it as an extension, so there were no changes to compiler behavior.
 
 Non-comprehensive list of changes in this release
 -------------------------------------------------