Re: [PATCH v2 08/35] built-ins: consistently add "\n" between "usage" and options

> Change commands in the "diff" family and "rev-list" to separate the
> usage information and option listing with an empty line.
>
> In the case of "git diff -h" we did this already (but let's use a
> consistent "\n" pattern there), for the rest these are now consistent
> with how the parse_options() API would emit usage.
>
> As we'll see in a subsequent commit this also helps to make the "git
> <cmd> -h" output more easily machine-readable, as we can assume that
> the usage usage information is separated from the options by an empty

> line.
>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
>  "git diff-files [-q] [-0 | -1 | -2 | -3 | -c | --cc] [<common-diff-options>] [<path>...]"
> +"\n"
>  COMMON_DIFF_OPTIONS_HELP;
>
>  "git diff-tree [--stdin] [-m] [-c | --cc] [-s] [-v] [--pretty] [-t] [-r] [--root] "
>  "[<common-diff-options>] <tree-ish> [<tree-ish>] [<path>...]\n"
> +"\n"
>  "  -r            diff recursively\n"