feat(menu.draw): columns can be function

[Parsifa1]

#820 may be closed

what i did:

• menu.draw.columns can receive an function with ctx args;
• draw.components._.width.max can receive an function with ctx args (this is needed for set seperate max_width for cmdline);

example

menu.draw.columns = function(ctx)
    if ctx.mode == "cmdline" then
        return { { "kind_icon" }, { "label" } }
    else
        return { { "kind_icon" }, { "label", "label_description", gap = 1 } }
    end
end

draw.components.label.width.max = function(ctx)
    return ctx.mode == "cmdline" and 20 or 60
end

need to do:

• docs
• config check should be more detailed.

feel free to change anything to what you want :)