PEP-790: initial draft

Author: Zac-HD

.github/CODEOWNERS

@@ -666,6 +666,7 @@ peps/pep-0784.rst  @gpshead
 peps/pep-0783.rst  @hoodmane @ambv
 # ...
 peps/pep-0789.rst  @njsmith
+peps/pep-0790.rst  @gpshead
 # ...
 peps/pep-0801.rst  @warsaw
 # ...