fix(mappings): allowing passing desc to mappings

[jamestrew]

Currently the map function in attach_mappings doesn't respect the desc option for vim.keymap.set which we use under the hood.
This results in anonymous functions to show up nameless, as <anonymous>, in which-key regardless of whether a desc is passed.

attach_mappings = function(_, map)
    map("i", "<C-f>", function() print("im anonymous") end, { desc = "hi" }) -- shows up as anonymous
end

closes #2888

[Conni2461]

Yeah makes sense thanks :)