nvim/lua/lsp/go.lua

return {
  settings = {
    gopls = {
      ui = {
        completion = {
          usePlaceholders = true,
        },
      },
    },
  },
  on_attach = function()
    G.api.nvim_create_user_command('R', function()
      G.cmd [[set splitbelow]]
      G.cmd [[sp]]
      G.cmd [[term go run %]]
      G.cmd [[startinsert]]
    end, {})
  end
}