These variables let you specify an editor that will be launched in
preference to the EDITOR and VISUAL environment variables. The order
of preference is GIT_EDITOR, core.editor, EDITOR, VISUAL.
[jc: added a test and config variable documentation]
Signed-off-by: Adam Roben <aroben@apple.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
