Revert "[clang-tidy] update ReleaseNotes.rst"

This reverts commit cca8471.

Author: dl8sd11

clang-tools-extra/docs/ReleaseNotes.rst

@@ -183,10 +183,6 @@ Changes in existing checks
   by adding the option `UseUpperCaseLiteralSuffix` to select the
   case of the literal suffix in fixes.
 
-- Improved :doc:`readability-redundant-casting
-  <clang-tidy/checks/readability/redundant-casting>` check to
-  exclude `CXXParenListInitExpr` for the source expression matcher.
-
 - Improved :doc:`readability-redundant-smartptr-get
   <clang-tidy/checks/readability/redundant-smartptr-get>` check to
   remove `->`, when redundant `get()` is removed.