Clangd configuration no more needed

[gabyx]

According to
p00f/clangd_extensions.nvim@643fd64

the setup

docs/docs/Recipes/advanced_lsp.md

Line 370 in 787c399

clangd = function(_, opts) require("clangd_extensions").setup { server = opts } end

can be ignored and then it works.

Is the identical now something like?

  clangd = function(server, opts)
    local lspconfig = require "lspconfig"
    lspconfig[server].setup(opts)
    require("clangd_extensions").setup()
  end,

I make a PR