gs lacks parsing of all short-hand permutations

[rsa2135]

Issue description

Currently gs only covers a handful (of the more common) status permutation that can occur between the working tree and the index. Specifically, ??, M, M, MM, D, D, DD, R, A, and A .
For all other short-hand permutations, an error is printed to the screen— TODO: UNKNOWN. FIX LATER...
Furthermore, many of the parsed statuses will not appear in all relevant states (to be committed, and not staged), but only in one.

Steps to reproduce the issue

1. Bring a file in your current branch to a permutation that is not supported.
   For example, a git status --porcelain output of AD added to index, deleted in tree.txt.txt and then

2. run gs

What's the expected result?

➤ Changes to be committed:

#        new file:  [1] added to index, deleted in tree.txt

➤ Changes not staged for commit:

#         deleted: [2] added to index, deleted in tree.txt

What's the actual result?

➤ Changes to be committed:

AD "added to index, deleted in tree.txt"
TODO: UNKNOWN. FIX LATER...

Additional details / screenshot

Here's an example of an output the shows quite a few of these issues

[rsa2135]

Would love to contribute, but I'm getting 403 when trying to push. Is the error on my end or is is the repo currently on read-only mode?

[jdelStrother]

If you fork it and submit a pull request I can merge it in.

[shinriyo]

or is is the repo currently on read-only mode?

No it isn't

thank you for your contributed

[rsa2135]

Hey, I linked a PR. Here's a screenshot of gss output on the same change list as the output above.

Please let me know if you see any issues.