Update peps/pep-0782.rst

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

Author: vstinner

peps/pep-0782.rst

@@ -11,7 +11,7 @@ Post-History:
 Resolution: `11-Sep-2025 <https://discuss.python.org/t/86617/15>`__
 
 
-.. canonical-doc:: the `PyBytesWriter API <https://docs.python.org/dev/c-api/bytes.html#pybyteswriter>`_
+.. canonical-doc:: the :ref:`PyBytesWriter API <py3.15:pybyteswriter>`
 
 .. highlight:: c