git-config: Improve documentation of git-config file handling
git-config: Improve documentation of git-config file handling

The description which files git-config uses and how the various
command line options and environment variables affect its
behaviour was incomplete, outdated and confusing.

Signed-off-by: Frank Lichtenheld <86a8c2da8527a1c6978bdca6d7986fe14ae147fe@lichtenheld.de>
Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git