Re: [PATCH v6 0/3] rebase: document, clean up, and introduce a config option for --rebase-merges

> Changes from v5:
> - Add commit message note about --no-rebase-merges having always worked
> - Add commit message note about the test for --no-rebase-merges being
>   somewhat contrived
> - Rephrase the documentation to avoid using the phrase "By default" with
>   two different meanings, and in so doing clarify that --rebase-merges
>   without an argument is not the same as --no-rebase-merges and not
>   passing --rebase-merges is not the same as passing
>   --rebase-merges=no-rebase-cousins
> - Add commit message note about keeping --rebase-merges="" for now out
>   of an abundance of caution
> - Rephrase the warning about --rebase-merges="" to recommend
>   --rebase-merges without an argument instead, and clarify that that
>   will do the same thing
> - Remove the test for --rebase-merges=""
> - Rename the config option from rebase.merges to rebase.rebaseMerges and
>   explain why in the commit message
> - Add commit message note about why "true" is a valid option for
>   rebase.rebaseMerges and why --rebase-merges without an argument does
>   not clobber the mode specified in rebase.rebaseMerges
> - Rephrase the documentation to clarify that --rebase-merges without an
>   argument does not clobber the mode specified in rebase.rebaseMerges
> - Add another test for incompatible options