Add a test for how 'git branch -m' handles the renaming of multiple
config sections existing for one branch.
The config format we use is hybrid machine/human editable, and we do
our best to preserve the likes of comments and formatting when editing
the file with git-config.
This adds a test for the currently expected semantics in the face of
some rather obscure edge cases which are unlikely to occur in
practice.
Helped-by: Sahil Dua <sahildua2305@gmail.com> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Sahil Dua <sahildua2305@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>