Floating help window for Neovim

floating-help.lua

function FloatingHelp(subject)
   local stats = vim.api.nvim_list_uis()[1]
   local width = math.ceil(stats.width * 0.8);
   local height = math.ceil(stats.height * 0.8);

   local buf = vim.api.nvim_create_buf(false, true)
   local winConfig = {
      relative = 'editor',
      width = width,
      height = height,
      col = math.ceil((stats.width - width) / 2),
      row = math.ceil((stats.height - height) / 2) - 1,
      border = 'single'
   }
   local winId = vim.api.nvim_open_win(buf, true, winConfig)

   vim.cmd.set('buftype=help')
   vim.cmd.help(subject)
end

-- usage: H or Help <topic>. Autocomplete is supported
vim.cmd("command! -nargs=1 -complete=help H :lua FloatingHelp(\"<args>\")<CR>")
vim.cmd("command! -nargs=1 -complete=help Help :lua FloatingHelp(\"<args>\")<CR>")