PEP 694: Updates (#3997)

* First round of changes

* Complete the major update/rewrite of the PEP

* Add a section on authentication

* Much updating, checkpointing

* Complete this phase of the rewrite.  One more pass to go!

* Fix some links and lints

* Minor updates

* Last round of updates

* Add myself to CODEOWNERS for PEP 694

Author: warsaw

.github/CODEOWNERS

@@ -574,7 +574,7 @@ peps/pep-0690.rst  @warsaw
 peps/pep-0691.rst  @dstufft
 peps/pep-0692.rst  @jellezijlstra
 peps/pep-0693.rst  @Yhg1s
-peps/pep-0694.rst  @dstufft
+peps/pep-0694.rst  @dstufft @warsaw
 peps/pep-0695.rst  @gvanrossum
 peps/pep-0696.rst  @jellezijlstra
 peps/pep-0697.rst  @encukou