Add release note

Author: JonathanMarriott

clang/docs/ReleaseNotes.rst

@@ -893,6 +893,7 @@ Bug Fixes to AST Handling
 - Fixed a malformed printout of certain calling convention function attributes. (#GH143160)
 - Fixed dependency calculation for TypedefTypes (#GH89774)
 - Fixed the right parenthesis source location of ``CXXTemporaryObjectExpr``. (#GH143711)
+- Fixed a crash when performing an ``IgnoreUnlessSpelledInSource`` traversal of ASTs containing ``catch(...)`` statements. (#GH146103)
 
 Miscellaneous Bug Fixes
 ^^^^^^^^^^^^^^^^^^^^^^^