Document change in the release notes

Author: FabianWolff

clang-tools-extra/docs/ReleaseNotes.rst

@@ -249,6 +249,10 @@ Changes in existing checks
   <clang-tidy/checks/readability/qualified-auto>` check by adding the option
   `AllowedTypes`, that excludes specified types from adding qualifiers.
 
+- Improved :doc:`readability-redundant-smartptr-get
+  <clang-tidy/checks/readability/redundant-smartptr-get>` check by fixing
+  some false positives involving smart pointers to arrays.
+
 Removed checks
 ^^^^^^^^^^^^^^