Re: [PATCH] docs: clarify meaning of core.commentString=auto

Phillip Wood [off-list ref] writes:

I think we'd want to start printing some advice when
core.commentStr=auto explaining why it has been deprecated and that it
will be removed when Git 3.0 is released. We should allow that advice
to be suppressed setting advice.autoCommentStr (other name suggestions
welcome). We would also want to add an item to BreakingChanges.adoc
explaining why it is being removed and add "#ifndef
WITH_BREAKING_CHANGES" around the code that handles
core.commentStr=auto in builtin/commit.c and guard the documentation
with "ifdef::with_breaking_changes[]".

All of these are good action items in a good transition plan, I
would say.

We may want to make
core.commentStr=auto an error when breaking changes are enabled as
well.

I am not so sure.  As commentStr is a random string that is used to
prefix any comment line, "auto" is just a (albeit weird) string, so
not doing anything special would be good enough.