users-guide: Note multiple pattern signature change in relnotes

docs/users_guide/8.2.1-notes.rst

@@ -22,6 +22,9 @@ Language
 
 -  TODO FIXME.
 
+- Pattern synonym signatures can now be applied to multiple patterns, just like
+  value-level binding signatures. See :ref:`patsyn-typing` for details.
+
 Compiler
 ~~~~~~~~
 

docs/users_guide/glasgow_exts.rst

@@ -4256,6 +4256,9 @@ A module which imports ``MyNum(..)`` from ``Example`` and then re-exports
 ``Example``. A more complete specification can be found on the
 :ghc-wiki:`wiki. <PatternSynonyms/AssociatingSynonyms>`
 
+
+.. _patsyn-typing:
+
 Typing of pattern synonyms
 --------------------------