Post-publishing cleanup for PEP 584 (#1298)

pep-0584.rst

@@ -10,7 +10,7 @@ Type: Standards Track
 Content-Type: text/x-rst
 Created: 01-Mar-2019
 Python-Version: 3.9
-Post-History: 01-Mar-2019, 16-Oct-2019, 05-Feb-2020
+Post-History: 01-Mar-2019, 16-Oct-2019, 04-Feb-2020
 Resolution:
 
 
@@ -350,9 +350,9 @@ Response
 This is very true.  But it is equally true today, where the use of the
 ``|`` operator could mean any of:
 
-  - ``int``/``bool`` bitwise-or
-  - ``set``/``frozenset`` union
-  - any other overloaded operation
+- ``int``/``bool`` bitwise-or
+- ``set``/``frozenset`` union
+- any other overloaded operation
 
 Adding dict union to the set of possibilities doesn't seem to make
 it *harder* to understand the code.  No more work is required to
@@ -863,7 +863,6 @@ sphinx/quickstart.py
 
 Before::
 
-    d.setdefault('release', d['version'])
     d2 = DEFAULT_VALUE.copy()
     d2.update(dict(("ext_"+ext, False) for ext in EXTENSIONS))
     d2.update(d)
@@ -964,6 +963,9 @@ Mailing list threads (this is by no means an exhaustive list):
 * `Moving PEP 584 forward (dict + and += operators)
   <https://mail.python.org/archives/list/python-ideas@python.org/thread/SWBLMTNQXNL3O5LN3327IYNPFIL2QSH5/>`_
 
+* `PEP 584: Add Union Operators To dict
+  <https://mail.python.org/archives/list/python-dev@python.org/thread/TTIKCDIPC2CDHX23Y57CPHDSVYOWCCER/>`_
+
 `Ticket on the bug tracker <https://bugs.python.org/issue36144>`_
 
 Merging two dictionaries in an expression is a frequently requested