How to add options like `{ expr = true, noremap = true, silent = true, nowait = true }`

[NWang]

As title.

[TJ DeVries]

Hi, I just added expr in latest commit, but you can do it like this:

vim.keymap.nmap {
  "<leader>t",

  function()
    return "<Plug>PlenaryTestFile"
  end,

  expr = true,
}

after the plugin has already been loaded

[NWang]

It will be very helpful for me if you could also update the README.md. Thanks!