[clang-tidy] Add a release note about unchecked-optional-access smart pointer caching

With caching added in llvm#120249,
inform in notes that the `IgnoreSmartPointerDereference` option shouldn't
be needed anymore.

Other caching also added earlier:
llvm#112605

Author: jvoung

clang-tools-extra/docs/ReleaseNotes.rst

@@ -232,6 +232,9 @@ Changes in existing checks
   <clang-tidy/checks/bugprone/unchecked-optional-access>` to support
   `bsl::optional` and `bdlb::NullableValue` from
   <https://github.com/bloomberg/bde>_.
+  Fixed false positives from smart pointer accessors repeated in checking
+  ``has_value`` and accessing ``value`` are now fixed by now caching.
+  So the option `IgnoreSmartPointerDereference` should no longer be needed.
 
 - Improved :doc:`bugprone-unhandled-self-assignment
   <clang-tidy/checks/bugprone/unhandled-self-assignment>` check by fixing smart