ReleaseNote: Mention SpecialCaseList change (#89141)

Co-authored-by: Paul T Robinson <[email protected]>

Author: MaskRay

llvm/docs/ReleaseNotes.rst

@@ -435,6 +435,13 @@ Changes to Sanitizers
 ---------------------
 * HWASan now defaults to detecting use-after-scope bugs.
 
+* `SpecialCaseList <https://clang.llvm.org/docs/SanitizerSpecialCaseList.html#format>`_
+  used by sanitizer ignore lists (e.g. ``*_ignorelist.txt`` in the Clang
+  resource directory) now uses glob patterns instead of a variant of POSIX
+  Extended Regular Expression (where ``*`` is translated to ``.*``) by default.
+  Search for ``|`` to find patterns that may have different meanings now, and
+  replace ``a|b`` with ``{a,b}``.
+
 Changes to the Profile Runtime
 ------------------------------