PEP 621: mention that '{name} <{email}>' may need quoting (#1861)

Author: takluyver

pep-0621.rst

@@ -292,7 +292,8 @@ Using the data to fill in `core metadata`_ is as follows:
    ``Author-email``/``Maintainer-email`` as appropriate.
 3. If both ``email`` and ``name`` are provided, the value goes in
    ``Author-email``/``Maintainer-email`` as appropriate, with the
-   format ``{name} <{email}>``.
+   format ``{name} <{email}>`` (with appropriate quoting, e.g. using
+   ``email.headerregistry.Address``).
 4. Multiple values should be separated by commas.
 
 ``keywords``