Fix broken reference from changelog to PyPUG.

Author: jaraco

NEWS.rst

@@ -1161,7 +1161,7 @@ Changes
   .. warning::
      Please note that future releases of setuptools will halt the build process
      if a ``pyproject.toml`` file that does not match doc:`the PyPA Specification
-     <PyPUG:specifications/declaring-project-metadata>` is given.
+     <PyPUG:specifications/section-distribution-metadata>` is given.
 * #3215: Updated ``pyproject.toml`` validation, as generated by ``validate-pyproject==0.6.1``.
 * #3218: Prevented builds from erroring if the project specifies metadata via
   ``pyproject.toml``, but uses other files (e.g. ``setup.py``) to complement it,