Josh Marshall <joshua.r.marshall.1991@gmail.com> writes:

> When reading https://guix.gnu.org/manual/en/guix.html#Submitting-Patches
> I do not see guidance on this particular aspect of sending patches.
> What do I need to alter, and should those details be added to the
> manual?

It's not very prominent, but it's there:

  Please write commit logs in the ChangeLog format (see Change Logs in
  GNU Coding Standards); you can check the commit history for examples.

With a link to the GNU Coding Standards document:

  https://www.gnu.org/prep/standards/standards.html#Change-Logs

Perhaps we could include a condensed version as it borders on TL;DR.

>  git commit -am "Updating python-argon2-cffi to 20.1.0"

If you omit the -m, git will open your $EDITOR where you can contemplate
on how best to communicate what the patch does, and write over multiple
lines.  There are helper functions in Emacs to fill out the boring
"* gnu/packages/file-name.scm (variable):" part of the commit message.

When unsure, I recommend running "git log the-file.scm" and look at
previous commit messages for inspiration.

Thanks for persevering!  :-)