[docs][clang-tools-extra] Fix broken document link in ReleaseNotes.rst

Fixes the following error:
```
clang-tools-extra/docs/ReleaseNotes.rst:247: WARNING: unknown document: 'clang-tidy/checks/readability/readability-identifier-naming' [ref.doc]
```

Author: nicovank

clang-tools-extra/docs/ReleaseNotes.rst

@@ -245,7 +245,7 @@ Changes in existing checks
   remove `->`, when redundant `get()` is removed.
 
 - Improved :doc:`readability-identifier-naming
-  <clang-tidy/checks/readability/readability-identifier-naming>` check to
+  <clang-tidy/checks/readability/identifier-naming>` check to
   validate ``namespace`` aliases.
 
 Removed checks