Sort CODEOWNERS (#4359)

Author: hugovk

.github/CODEOWNERS

@@ -661,9 +661,8 @@ peps/pep-0779.rst  @Yhg1s @colesbury @mpage
 peps/pep-0780.rst  @lysnikolaou
 peps/pep-0781.rst  @methane
 peps/pep-0782.rst  @vstinner
-peps/pep-0784.rst  @gpshead
-# ...
 peps/pep-0783.rst  @hoodmane @ambv
+peps/pep-0784.rst  @gpshead
 # ...
 peps/pep-0789.rst  @njsmith
 # ...