Document git status -b --porcelain

Document git status -b --porcelain

[Ondra Medek]

Hi,

I am using "git status -b --porcelain" and parsing output in a code.
However, the output is not documented for an empty repository or a
missing remote branch. (And maybe a detached head, too).

Doc for Porcelain Format Version 1

https://git-scm.com/docs/git-status#_porcelain_format_version_1

references doc for Short Format

https://git-scm.com/docs/git-status#_short_format

and it says:

> If -b is used the short-format status is preceded by a line
>   ## branchname tracking info

However, when I have a fresh clone or an empty repository, "git status
-b --porcelain" results in:

## No commits yet on master...origin/master [gone]

So, it seems to me the format is something like "# [info1
]branchname...tracking[ info2]" and it should be documented what infos
may appear and when. Otherwise it's hard to write robust parsing of
such output.

Thanks
Ondra Medek