git-sugdiff: Use `diff_options.parse()` to extract diff options

Config::get():
Change `args` type so we can pass both a `Vec<String>` and
`Vec<&String>`.

diff_options.parse():
* Split diff arguments and program arguments by returning a tuple.
* Exit the args loop once we've parsed an argument.
* Update test
* Add a non-working test for suggestion arguments. An `OPT_OPTIONS`
  argument could be followed by an argument that's not the value of the
  `OPT_OPTIONS` option. Currently, that arg will always be parsed as the
  value. We need to handle this case.

0 files changed, 0 insertions, 0 deletions