Allow ++curwin option to come after other options

[KSR-Yasuda]

Why don't you allow ++curwin option to come after other options such as -p?

:G ++curwin -p log
" Already supported (the current option order).

:G -p ++curwin log
" Supported newly by this patch.

:G -p log ++curwin
" Not supported: the `++curwin` is treated as an argument for the git command.

I don't want to pay attention to the option order.