[PATCH] push: Re-include "push.default=tracking" in the documentation

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Change the documentation for push.tracking=* to re-include a mention
of what "tracking" does.

The "tracking" option was renamed to "upstream" back in
53c4031 ("push.default: Rename 'tracking' to 'upstream'", 2011-02-16),
this section was then subsequently rewritten in 87a70e4 ("config doc:
rewrite push.default section", 2013-06-19) to remove any mention of
"tracking".

Maybe we should just warn or die nowadays if this option is in the
config, but I had some old config of mine use this option, I'd
forgotten that it was a synonym, and nothing in git's documentation
mentioned that.

That's bad, either we shouldn't support it at all, or we should
document what it does. This patch does the latter.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Documentation/config.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 32f065c..f30d52a 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -2344,6 +2344,10 @@ push.default::
   pushing to the same repository you would normally pull from
   (i.e. central workflow).
 
+* `tracking` - Deprecated synonym for `upstream`, which we still
+  support for backwards compatibility with existing configuration
+  files.
+
 * `simple` - in centralized workflow, work like `upstream` with an
   added safety to refuse to push if the upstream branch's name is
   different from the local one.
-- 
2.9.3