no sway.desktop file for GDM

[Fredrik Salomonsson]

Hi Guix,

Is there a reason why the sway package doesn't create a sway.desktop file
in *out*/share/wayland-sessons for GDM? I see that most X tiling wms create
on in *out*/share/xsessons.

I tried adding one myself by copying the code from herbstluftwm and modify
it but got stuck on permissions when I tried to run guix built from my
local clone. So before I continue debugging that I though I would ask.

Thanks
-- 
s/Fred[re]+i[ck]+/Fredrik/g