Fix ReST syntax error in the PEP 517 link

docs/userguide/quickstart.rst

@@ -22,7 +22,7 @@ be generated with whatever tools that provides a ``build sdist``-alike
 functionality. While this may appear cumbersome, given the added pieces,
 it in fact tremendously enhances the portability of your package. The
 change is driven under `PEP 517 <https://www.python.org/dev/peps/pep-0517/#
-build-requirements>``. To learn more about Python packaging in general,
+build-requirements>`_. To learn more about Python packaging in general,
 navigate to the `bottom <Resources on python packaging>`_ of this page.