optimize release notes

Author: flovent

clang-tools-extra/docs/ReleaseNotes.rst

@@ -218,7 +218,8 @@ Changes in existing checks
 
 - Improved :doc:`cppcoreguidelines-pro-bounds-pointer-arithmetic
   <clang-tidy/checks/cppcoreguidelines/pro-bounds-pointer-arithmetic>` check by
-  fix false positives related to operator overloading and templates.
+  fixing false positives when calling indexing operators that do not perform
+  pointer arithmetic in template, for example ``std::map::operator[]``.
 
 - Improved :doc:`cppcoreguidelines-rvalue-reference-param-not-moved
   <clang-tidy/checks/cppcoreguidelines/rvalue-reference-param-not-moved>` check