show numbers for every spell_suggest picker suggestions

[mortezadadgar]

Just a minimal improvement to make the picker output like the native neovim's z= key binding.

[nenahp]

I don't think that's a improvement... The reason why z= has a 1. xx/2. xx is that it share the same logic of inputlist, it's terrible that it can only return a digit, so we must use digit as a id for each line string:
https://github.com/neovim/neovim/blob/aa976f0d932738cb4b4f7cf5bef3d5157c68232d/src/nvim/input.c#L179

If you like it you can write a picker by yourself:

require('fzf-lua').fzf_exec(
  vim
    .iter(ipairs(vim.fn.spellsuggest(vim.fn.expand '<cword>')))
    :map(function(k, v) return ('%s. %s'):format(k, v) end)
    :totable(),
  {
    actions = {
      enter = function(sel)
        require('fzf-lua.actions').spell_apply({ (unpack(sel):match('%d%. (.*)$')) })
      end,
    },
  }
)