Add option for grouping directories at the top

[ghost]

ls already has something like this:

--group-directories-first
    group directories before files;

Basically what it would do is re-order fd output for displaying directories grouped at the top, before files, example below:

# before

a-file
b-folder-1
b-folder-2
c-file

# after (with -G)

b-folder-1
b-folder-2
a-file
c-file

The flag for this could be -G, as -g is already being used as the --glob option, and the description on the docs

[sharkdp]

Thank you very much for your contribution!

This is similar to a --sort option that we decided not to implement for various reasons (see #324, for example). What you can do is to pipe to ls -G:

fd … -X ls -lhd --color=always --group-directories-first

[ghost]

Many thanks @sharkdp, it worked!